1 d3_transitionPrototype.duration = function(value) {

     2   var groups = this;

     3   return groups.each(typeof value === "function"

     4       ? function(d, i, j) { groups[j][i].duration = +value.apply(this, arguments); }

     5       : (value = +value, function(d, i, j) { groups[j][i].duration = value; }));

     6 };