import chardet

def to_unicode(input):

    if type(input) == str:

        res = None

        for encoding in [chardet.detect(input)['encoding'], 'utf8', 'latin1']:

            try:

                res = unicode(input, encoding)

                break;

            except UnicodeDecodeError:

                pass

        if not res:

            raise Exception('UnicodeDecodeError: could not decode')

        return res

    return input