Some changes to SortedDict to make it faster under py2

import copy

import warnings

from types import GeneratorType

from django.utils import six

        return instance

    def __init__(self, data=None):

        if data is None:

            data = {}

        elif isinstance(data, GeneratorType):

            # Unfortunately we need to be able to read a generator twice.  Once

            # to get the data into self with our super().__init__ call and a

            # second time to setup keyOrder correctly

            data = list(data)

        if data is None or isinstance(data, dict):

            data = data or []

            super(SortedDict, self).__init__(data)

        if isinstance(data, dict):

            self.keyOrder = list(data)

            self.keyOrder = list(data) if data else []

        else:

            self.keyOrder = []

            seen = set()

            super(SortedDict, self).__init__()

            super_set = super(SortedDict, self).__setitem__

            for key, value in data:

                if key not in seen:

                # Take the ordering from first key

                if key not in self:

                    self.keyOrder.append(key)

                    seen.add(key)

                # But override with last value in data (dict() does this)

                super_set(key, value)

    def __deepcopy__(self, memo):

        return self.__class__([(key, copy.deepcopy(value, memo))

                               for key, value in six.iteritems(self)])

                               for key, value in self.items()])

    def __copy__(self):

        # The Python's default copy implementation will alter the state

        itervalues = _itervalues

        def items(self):

            return list(self.iteritems())

            return [(k, self[k]) for k in self.keyOrder]

        def keys(self):

            return list(self.iterkeys())

            return self.keyOrder[:]

        def values(self):

            return list(self.itervalues())

            return [self[k] for k in self.keyOrder]

    def update(self, dict_):

        for k, v in six.iteritems(dict_):