diff -r 000000000000 -r 0d40e90630ef web/lib/django/db/models/base.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/db/models/base.py	Wed Jan 20 00:34:04 2010 +0100
@@ -0,0 +1,664 @@
+import copy
+import types
+import sys
+import os
+from itertools import izip
+try:
+    set
+except NameError:
+    from sets import Set as set     # Python 2.3 fallback.
+
+import django.db.models.manager     # Imported to register signal handler.
+from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned, FieldError
+from django.db.models.fields import AutoField, FieldDoesNotExist
+from django.db.models.fields.related import OneToOneRel, ManyToOneRel, OneToOneField
+from django.db.models.query import delete_objects, Q
+from django.db.models.query_utils import CollectedObjects, DeferredAttribute
+from django.db.models.options import Options
+from django.db import connection, transaction, DatabaseError
+from django.db.models import signals
+from django.db.models.loading import register_models, get_model
+from django.utils.functional import curry
+from django.utils.encoding import smart_str, force_unicode, smart_unicode
+from django.conf import settings
+
+
+class ModelBase(type):
+    """
+    Metaclass for all models.
+    """
+    def __new__(cls, name, bases, attrs):
+        super_new = super(ModelBase, cls).__new__
+        parents = [b for b in bases if isinstance(b, ModelBase)]
+        if not parents:
+            # If this isn't a subclass of Model, don't do anything special.
+            return super_new(cls, name, bases, attrs)
+
+        # Create the class.
+        module = attrs.pop('__module__')
+        new_class = super_new(cls, name, bases, {'__module__': module})
+        attr_meta = attrs.pop('Meta', None)
+        abstract = getattr(attr_meta, 'abstract', False)
+        if not attr_meta:
+            meta = getattr(new_class, 'Meta', None)
+        else:
+            meta = attr_meta
+        base_meta = getattr(new_class, '_meta', None)
+
+        if getattr(meta, 'app_label', None) is None:
+            # Figure out the app_label by looking one level up.
+            # For 'django.contrib.sites.models', this would be 'sites'.
+            model_module = sys.modules[new_class.__module__]
+            kwargs = {"app_label": model_module.__name__.split('.')[-2]}
+        else:
+            kwargs = {}
+
+        new_class.add_to_class('_meta', Options(meta, **kwargs))
+        if not abstract:
+            new_class.add_to_class('DoesNotExist',
+                    subclass_exception('DoesNotExist', ObjectDoesNotExist, module))
+            new_class.add_to_class('MultipleObjectsReturned',
+                    subclass_exception('MultipleObjectsReturned', MultipleObjectsReturned, module))
+            if base_meta and not base_meta.abstract:
+                # Non-abstract child classes inherit some attributes from their
+                # non-abstract parent (unless an ABC comes before it in the
+                # method resolution order).
+                if not hasattr(meta, 'ordering'):
+                    new_class._meta.ordering = base_meta.ordering
+                if not hasattr(meta, 'get_latest_by'):
+                    new_class._meta.get_latest_by = base_meta.get_latest_by
+
+        is_proxy = new_class._meta.proxy
+
+        if getattr(new_class, '_default_manager', None):
+            if not is_proxy:
+                # Multi-table inheritance doesn't inherit default manager from
+                # parents.
+                new_class._default_manager = None
+                new_class._base_manager = None
+            else:
+                # Proxy classes do inherit parent's default manager, if none is
+                # set explicitly.
+                new_class._default_manager = new_class._default_manager._copy_to_model(new_class)
+                new_class._base_manager = new_class._base_manager._copy_to_model(new_class)
+
+        # Bail out early if we have already created this class.
+        m = get_model(new_class._meta.app_label, name, False)
+        if m is not None:
+            return m
+
+        # Add all attributes to the class.
+        for obj_name, obj in attrs.items():
+            new_class.add_to_class(obj_name, obj)
+
+        # All the fields of any type declared on this model
+        new_fields = new_class._meta.local_fields + \
+                     new_class._meta.local_many_to_many + \
+                     new_class._meta.virtual_fields
+        field_names = set([f.name for f in new_fields])
+
+        # Basic setup for proxy models.
+        if is_proxy:
+            base = None
+            for parent in [cls for cls in parents if hasattr(cls, '_meta')]:
+                if parent._meta.abstract:
+                    if parent._meta.fields:
+                        raise TypeError("Abstract base class containing model fields not permitted for proxy model '%s'." % name)
+                    else:
+                        continue
+                if base is not None:
+                    raise TypeError("Proxy model '%s' has more than one non-abstract model base class." % name)
+                else:
+                    base = parent
+            if base is None:
+                    raise TypeError("Proxy model '%s' has no non-abstract model base class." % name)
+            if (new_class._meta.local_fields or
+                    new_class._meta.local_many_to_many):
+                raise FieldError("Proxy model '%s' contains model fields."
+                        % name)
+            while base._meta.proxy:
+                base = base._meta.proxy_for_model
+            new_class._meta.setup_proxy(base)
+
+        # Do the appropriate setup for any model parents.
+        o2o_map = dict([(f.rel.to, f) for f in new_class._meta.local_fields
+                if isinstance(f, OneToOneField)])
+
+        for base in parents:
+            original_base = base
+            if not hasattr(base, '_meta'):
+                # Things without _meta aren't functional models, so they're
+                # uninteresting parents.
+                continue
+
+            parent_fields = base._meta.local_fields + base._meta.local_many_to_many
+            # Check for clashes between locally declared fields and those
+            # on the base classes (we cannot handle shadowed fields at the
+            # moment).
+            for field in parent_fields:
+                if field.name in field_names:
+                    raise FieldError('Local field %r in class %r clashes '
+                                     'with field of similar name from '
+                                     'base class %r' %
+                                        (field.name, name, base.__name__))
+            if not base._meta.abstract:
+                # Concrete classes...
+                while base._meta.proxy:
+                    # Skip over a proxy class to the "real" base it proxies.
+                    base = base._meta.proxy_for_model
+                if base in o2o_map:
+                    field = o2o_map[base]
+                elif not is_proxy:
+                    attr_name = '%s_ptr' % base._meta.module_name
+                    field = OneToOneField(base, name=attr_name,
+                            auto_created=True, parent_link=True)
+                    new_class.add_to_class(attr_name, field)
+                else:
+                    field = None
+                new_class._meta.parents[base] = field
+            else:
+                # .. and abstract ones.
+                for field in parent_fields:
+                    new_class.add_to_class(field.name, copy.deepcopy(field))
+
+                # Pass any non-abstract parent classes onto child.
+                new_class._meta.parents.update(base._meta.parents)
+
+            # Inherit managers from the abstract base classes.
+            new_class.copy_managers(base._meta.abstract_managers)
+
+            # Proxy models inherit the non-abstract managers from their base,
+            # unless they have redefined any of them.
+            if is_proxy:
+                new_class.copy_managers(original_base._meta.concrete_managers)
+
+            # Inherit virtual fields (like GenericForeignKey) from the parent
+            # class
+            for field in base._meta.virtual_fields:
+                if base._meta.abstract and field.name in field_names:
+                    raise FieldError('Local field %r in class %r clashes '\
+                                     'with field of similar name from '\
+                                     'abstract base class %r' % \
+                                        (field.name, name, base.__name__))
+                new_class.add_to_class(field.name, copy.deepcopy(field))
+
+        if abstract:
+            # Abstract base models can't be instantiated and don't appear in
+            # the list of models for an app. We do the final setup for them a
+            # little differently from normal models.
+            attr_meta.abstract = False
+            new_class.Meta = attr_meta
+            return new_class
+
+        new_class._prepare()
+        register_models(new_class._meta.app_label, new_class)
+
+        # Because of the way imports happen (recursively), we may or may not be
+        # the first time this model tries to register with the framework. There
+        # should only be one class for each model, so we always return the
+        # registered version.
+        return get_model(new_class._meta.app_label, name, False)
+
+    def copy_managers(cls, base_managers):
+        # This is in-place sorting of an Options attribute, but that's fine.
+        base_managers.sort()
+        for _, mgr_name, manager in base_managers:
+            val = getattr(cls, mgr_name, None)
+            if not val or val is manager:
+                new_manager = manager._copy_to_model(cls)
+                cls.add_to_class(mgr_name, new_manager)
+
+    def add_to_class(cls, name, value):
+        if hasattr(value, 'contribute_to_class'):
+            value.contribute_to_class(cls, name)
+        else:
+            setattr(cls, name, value)
+
+    def _prepare(cls):
+        """
+        Creates some methods once self._meta has been populated.
+        """
+        opts = cls._meta
+        opts._prepare(cls)
+
+        if opts.order_with_respect_to:
+            cls.get_next_in_order = curry(cls._get_next_or_previous_in_order, is_next=True)
+            cls.get_previous_in_order = curry(cls._get_next_or_previous_in_order, is_next=False)
+            setattr(opts.order_with_respect_to.rel.to, 'get_%s_order' % cls.__name__.lower(), curry(method_get_order, cls))
+            setattr(opts.order_with_respect_to.rel.to, 'set_%s_order' % cls.__name__.lower(), curry(method_set_order, cls))
+
+        # Give the class a docstring -- its definition.
+        if cls.__doc__ is None:
+            cls.__doc__ = "%s(%s)" % (cls.__name__, ", ".join([f.attname for f in opts.fields]))
+
+        if hasattr(cls, 'get_absolute_url'):
+            cls.get_absolute_url = curry(get_absolute_url, opts, cls.get_absolute_url)
+
+        signals.class_prepared.send(sender=cls)
+
+
+class Model(object):
+    __metaclass__ = ModelBase
+    _deferred = False
+
+    def __init__(self, *args, **kwargs):
+        signals.pre_init.send(sender=self.__class__, args=args, kwargs=kwargs)
+
+        # There is a rather weird disparity here; if kwargs, it's set, then args
+        # overrides it. It should be one or the other; don't duplicate the work
+        # The reason for the kwargs check is that standard iterator passes in by
+        # args, and instantiation for iteration is 33% faster.
+        args_len = len(args)
+        if args_len > len(self._meta.fields):
+            # Daft, but matches old exception sans the err msg.
+            raise IndexError("Number of args exceeds number of fields")
+
+        fields_iter = iter(self._meta.fields)
+        if not kwargs:
+            # The ordering of the izip calls matter - izip throws StopIteration
+            # when an iter throws it. So if the first iter throws it, the second
+            # is *not* consumed. We rely on this, so don't change the order
+            # without changing the logic.
+            for val, field in izip(args, fields_iter):
+                setattr(self, field.attname, val)
+        else:
+            # Slower, kwargs-ready version.
+            for val, field in izip(args, fields_iter):
+                setattr(self, field.attname, val)
+                kwargs.pop(field.name, None)
+                # Maintain compatibility with existing calls.
+                if isinstance(field.rel, ManyToOneRel):
+                    kwargs.pop(field.attname, None)
+
+        # Now we're left with the unprocessed fields that *must* come from
+        # keywords, or default.
+
+        for field in fields_iter:
+            is_related_object = False
+            # This slightly odd construct is so that we can access any
+            # data-descriptor object (DeferredAttribute) without triggering its
+            # __get__ method.
+            if (field.attname not in kwargs and
+                    isinstance(self.__class__.__dict__.get(field.attname), DeferredAttribute)):
+                # This field will be populated on request.
+                continue
+            if kwargs:
+                if isinstance(field.rel, ManyToOneRel):
+                    try:
+                        # Assume object instance was passed in.
+                        rel_obj = kwargs.pop(field.name)
+                        is_related_object = True
+                    except KeyError:
+                        try:
+                            # Object instance wasn't passed in -- must be an ID.
+                            val = kwargs.pop(field.attname)
+                        except KeyError:
+                            val = field.get_default()
+                    else:
+                        # Object instance was passed in. Special case: You can
+                        # pass in "None" for related objects if it's allowed.
+                        if rel_obj is None and field.null:
+                            val = None
+                else:
+                    val = kwargs.pop(field.attname, field.get_default())
+            else:
+                val = field.get_default()
+            if is_related_object:
+                # If we are passed a related instance, set it using the
+                # field.name instead of field.attname (e.g. "user" instead of
+                # "user_id") so that the object gets properly cached (and type
+                # checked) by the RelatedObjectDescriptor.
+                setattr(self, field.name, rel_obj)
+            else:
+                setattr(self, field.attname, val)
+
+        if kwargs:
+            for prop in kwargs.keys():
+                try:
+                    if isinstance(getattr(self.__class__, prop), property):
+                        setattr(self, prop, kwargs.pop(prop))
+                except AttributeError:
+                    pass
+            if kwargs:
+                raise TypeError, "'%s' is an invalid keyword argument for this function" % kwargs.keys()[0]
+        signals.post_init.send(sender=self.__class__, instance=self)
+
+    def __repr__(self):
+        try:
+            u = unicode(self)
+        except (UnicodeEncodeError, UnicodeDecodeError):
+            u = '[Bad Unicode data]'
+        return smart_str(u'<%s: %s>' % (self.__class__.__name__, u))
+
+    def __str__(self):
+        if hasattr(self, '__unicode__'):
+            return force_unicode(self).encode('utf-8')
+        return '%s object' % self.__class__.__name__
+
+    def __eq__(self, other):
+        return isinstance(other, self.__class__) and self._get_pk_val() == other._get_pk_val()
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
+    def __hash__(self):
+        return hash(self._get_pk_val())
+
+    def __reduce__(self):
+        """
+        Provide pickling support. Normally, this just dispatches to Python's
+        standard handling. However, for models with deferred field loading, we
+        need to do things manually, as they're dynamically created classes and
+        only module-level classes can be pickled by the default path.
+        """
+        data = self.__dict__
+        if not self._deferred:
+            return (self.__class__, (), data)
+        defers = []
+        pk_val = None
+        for field in self._meta.fields:
+            if isinstance(self.__class__.__dict__.get(field.attname),
+                    DeferredAttribute):
+                defers.append(field.attname)
+                if pk_val is None:
+                    # The pk_val and model values are the same for all
+                    # DeferredAttribute classes, so we only need to do this
+                    # once.
+                    obj = self.__class__.__dict__[field.attname]
+                    model = obj.model_ref()
+        return (model_unpickle, (model, defers), data)
+
+    def _get_pk_val(self, meta=None):
+        if not meta:
+            meta = self._meta
+        return getattr(self, meta.pk.attname)
+
+    def _set_pk_val(self, value):
+        return setattr(self, self._meta.pk.attname, value)
+
+    pk = property(_get_pk_val, _set_pk_val)
+
+    def serializable_value(self, field_name):
+        """
+        Returns the value of the field name for this instance. If the field is
+        a foreign key, returns the id value, instead of the object. If there's
+        no Field object with this name on the model, the model attribute's
+        value is returned directly.
+
+        Used to serialize a field's value (in the serializer, or form output,
+        for example). Normally, you would just access the attribute directly
+        and not use this method.
+        """
+        try:
+            field = self._meta.get_field_by_name(field_name)[0]
+        except FieldDoesNotExist:
+            return getattr(self, field_name)
+        return getattr(self, field.attname)
+
+    def save(self, force_insert=False, force_update=False):
+        """
+        Saves the current instance. Override this in a subclass if you want to
+        control the saving process.
+
+        The 'force_insert' and 'force_update' parameters can be used to insist
+        that the "save" must be an SQL insert or update (or equivalent for
+        non-SQL backends), respectively. Normally, they should not be set.
+        """
+        if force_insert and force_update:
+            raise ValueError("Cannot force both insert and updating in "
+                    "model saving.")
+        self.save_base(force_insert=force_insert, force_update=force_update)
+
+    save.alters_data = True
+
+    def save_base(self, raw=False, cls=None, origin=None,
+            force_insert=False, force_update=False):
+        """
+        Does the heavy-lifting involved in saving. Subclasses shouldn't need to
+        override this method. It's separate from save() in order to hide the
+        need for overrides of save() to pass around internal-only parameters
+        ('raw', 'cls', and 'origin').
+        """
+        assert not (force_insert and force_update)
+        if cls is None:
+            cls = self.__class__
+            meta = cls._meta
+            if not meta.proxy:
+                origin = cls
+        else:
+            meta = cls._meta
+
+        if origin:
+            signals.pre_save.send(sender=origin, instance=self, raw=raw)
+
+        # If we are in a raw save, save the object exactly as presented.
+        # That means that we don't try to be smart about saving attributes
+        # that might have come from the parent class - we just save the
+        # attributes we have been given to the class we have been given.
+        # We also go through this process to defer the save of proxy objects
+        # to their actual underlying model.
+        if not raw or meta.proxy:
+            if meta.proxy:
+                org = cls
+            else:
+                org = None
+            for parent, field in meta.parents.items():
+                # At this point, parent's primary key field may be unknown
+                # (for example, from administration form which doesn't fill
+                # this field). If so, fill it.
+                if field and getattr(self, parent._meta.pk.attname) is None and getattr(self, field.attname) is not None:
+                    setattr(self, parent._meta.pk.attname, getattr(self, field.attname))
+
+                self.save_base(cls=parent, origin=org)
+
+                if field:
+                    setattr(self, field.attname, self._get_pk_val(parent._meta))
+            if meta.proxy:
+                return
+
+        if not meta.proxy:
+            non_pks = [f for f in meta.local_fields if not f.primary_key]
+
+            # First, try an UPDATE. If that doesn't update anything, do an INSERT.
+            pk_val = self._get_pk_val(meta)
+            pk_set = pk_val is not None
+            record_exists = True
+            manager = cls._base_manager
+            if pk_set:
+                # Determine whether a record with the primary key already exists.
+                if (force_update or (not force_insert and
+                        manager.filter(pk=pk_val).extra(select={'a': 1}).values('a').order_by())):
+                    # It does already exist, so do an UPDATE.
+                    if force_update or non_pks:
+                        values = [(f, None, (raw and getattr(self, f.attname) or f.pre_save(self, False))) for f in non_pks]
+                        rows = manager.filter(pk=pk_val)._update(values)
+                        if force_update and not rows:
+                            raise DatabaseError("Forced update did not affect any rows.")
+                else:
+                    record_exists = False
+            if not pk_set or not record_exists:
+                if not pk_set:
+                    if force_update:
+                        raise ValueError("Cannot force an update in save() with no primary key.")
+                    values = [(f, f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, True))) for f in meta.local_fields if not isinstance(f, AutoField)]
+                else:
+                    values = [(f, f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, True))) for f in meta.local_fields]
+
+                if meta.order_with_respect_to:
+                    field = meta.order_with_respect_to
+                    values.append((meta.get_field_by_name('_order')[0], manager.filter(**{field.name: getattr(self, field.attname)}).count()))
+                record_exists = False
+
+                update_pk = bool(meta.has_auto_field and not pk_set)
+                if values:
+                    # Create a new record.
+                    result = manager._insert(values, return_id=update_pk)
+                else:
+                    # Create a new record with defaults for everything.
+                    result = manager._insert([(meta.pk, connection.ops.pk_default_value())], return_id=update_pk, raw_values=True)
+
+                if update_pk:
+                    setattr(self, meta.pk.attname, result)
+            transaction.commit_unless_managed()
+
+        if origin:
+            signals.post_save.send(sender=origin, instance=self,
+                created=(not record_exists), raw=raw)
+
+    save_base.alters_data = True
+
+    def _collect_sub_objects(self, seen_objs, parent=None, nullable=False):
+        """
+        Recursively populates seen_objs with all objects related to this
+        object.
+
+        When done, seen_objs.items() will be in the format:
+            [(model_class, {pk_val: obj, pk_val: obj, ...}),
+             (model_class, {pk_val: obj, pk_val: obj, ...}), ...]
+        """
+        pk_val = self._get_pk_val()
+        if seen_objs.add(self.__class__, pk_val, self, parent, nullable):
+            return
+
+        for related in self._meta.get_all_related_objects():
+            rel_opts_name = related.get_accessor_name()
+            if isinstance(related.field.rel, OneToOneRel):
+                try:
+                    sub_obj = getattr(self, rel_opts_name)
+                except ObjectDoesNotExist:
+                    pass
+                else:
+                    sub_obj._collect_sub_objects(seen_objs, self.__class__, related.field.null)
+            else:
+                # To make sure we can access all elements, we can't use the
+                # normal manager on the related object. So we work directly
+                # with the descriptor object.
+                for cls in self.__class__.mro():
+                    if rel_opts_name in cls.__dict__:
+                        rel_descriptor = cls.__dict__[rel_opts_name]
+                        break
+                else:
+                    raise AssertionError("Should never get here.")
+                delete_qs = rel_descriptor.delete_manager(self).all()
+                for sub_obj in delete_qs:
+                    sub_obj._collect_sub_objects(seen_objs, self.__class__, related.field.null)
+
+        # Handle any ancestors (for the model-inheritance case). We do this by
+        # traversing to the most remote parent classes -- those with no parents
+        # themselves -- and then adding those instances to the collection. That
+        # will include all the child instances down to "self".
+        parent_stack = [p for p in self._meta.parents.values() if p is not None]
+        while parent_stack:
+            link = parent_stack.pop()
+            parent_obj = getattr(self, link.name)
+            if parent_obj._meta.parents:
+                parent_stack.extend(parent_obj._meta.parents.values())
+                continue
+            # At this point, parent_obj is base class (no ancestor models). So
+            # delete it and all its descendents.
+            parent_obj._collect_sub_objects(seen_objs)
+
+    def delete(self):
+        assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname)
+
+        # Find all the objects than need to be deleted.
+        seen_objs = CollectedObjects()
+        self._collect_sub_objects(seen_objs)
+
+        # Actually delete the objects.
+        delete_objects(seen_objs)
+
+    delete.alters_data = True
+
+    def _get_FIELD_display(self, field):
+        value = getattr(self, field.attname)
+        return force_unicode(dict(field.flatchoices).get(value, value), strings_only=True)
+
+    def _get_next_or_previous_by_FIELD(self, field, is_next, **kwargs):
+        op = is_next and 'gt' or 'lt'
+        order = not is_next and '-' or ''
+        param = smart_str(getattr(self, field.attname))
+        q = Q(**{'%s__%s' % (field.name, op): param})
+        q = q|Q(**{field.name: param, 'pk__%s' % op: self.pk})
+        qs = self.__class__._default_manager.filter(**kwargs).filter(q).order_by('%s%s' % (order, field.name), '%spk' % order)
+        try:
+            return qs[0]
+        except IndexError:
+            raise self.DoesNotExist, "%s matching query does not exist." % self.__class__._meta.object_name
+
+    def _get_next_or_previous_in_order(self, is_next):
+        cachename = "__%s_order_cache" % is_next
+        if not hasattr(self, cachename):
+            qn = connection.ops.quote_name
+            op = is_next and '>' or '<'
+            order = not is_next and '-_order' or '_order'
+            order_field = self._meta.order_with_respect_to
+            # FIXME: When querysets support nested queries, this can be turned
+            # into a pure queryset operation.
+            where = ['%s %s (SELECT %s FROM %s WHERE %s=%%s)' % \
+                (qn('_order'), op, qn('_order'),
+                qn(self._meta.db_table), qn(self._meta.pk.column))]
+            params = [self.pk]
+            obj = self._default_manager.filter(**{order_field.name: getattr(self, order_field.attname)}).extra(where=where, params=params).order_by(order)[:1].get()
+            setattr(self, cachename, obj)
+        return getattr(self, cachename)
+
+    def prepare_database_save(self, unused):
+        return self.pk
+
+
+############################################
+# HELPER FUNCTIONS (CURRIED MODEL METHODS) #
+############################################
+
+# ORDERING METHODS #########################
+
+def method_set_order(ordered_obj, self, id_list):
+    rel_val = getattr(self, ordered_obj._meta.order_with_respect_to.rel.field_name)
+    order_name = ordered_obj._meta.order_with_respect_to.name
+    # FIXME: It would be nice if there was an "update many" version of update
+    # for situations like this.
+    for i, j in enumerate(id_list):
+        ordered_obj.objects.filter(**{'pk': j, order_name: rel_val}).update(_order=i)
+    transaction.commit_unless_managed()
+
+
+def method_get_order(ordered_obj, self):
+    rel_val = getattr(self, ordered_obj._meta.order_with_respect_to.rel.field_name)
+    order_name = ordered_obj._meta.order_with_respect_to.name
+    pk_name = ordered_obj._meta.pk.name
+    return [r[pk_name] for r in
+            ordered_obj.objects.filter(**{order_name: rel_val}).values(pk_name)]
+
+
+##############################################
+# HELPER FUNCTIONS (CURRIED MODEL FUNCTIONS) #
+##############################################
+
+def get_absolute_url(opts, func, self, *args, **kwargs):
+    return settings.ABSOLUTE_URL_OVERRIDES.get('%s.%s' % (opts.app_label, opts.module_name), func)(self, *args, **kwargs)
+
+
+########
+# MISC #
+########
+
+class Empty(object):
+    pass
+
+def model_unpickle(model, attrs):
+    """
+    Used to unpickle Model subclasses with deferred fields.
+    """
+    from django.db.models.query_utils import deferred_class_factory
+    cls = deferred_class_factory(model, attrs)
+    return cls.__new__(cls)
+model_unpickle.__safe_for_unpickle__ = True
+
+if sys.version_info < (2, 5):
+    # Prior to Python 2.5, Exception was an old-style class
+    def subclass_exception(name, parent, unused):
+        return types.ClassType(name, (parent,), {})
+else:
+    def subclass_exception(name, parent, module):
+        return type(name, (parent,), {'__module__': module})