def __init__(self, *args, **kwds):

            if len(args) > 1:
                raise TypeError('expected at most 1 arguments, got %d' % len(args))
            try:
                self.__end
            except AttributeError:
                self.clear()
            self.update(*args, **kwds)
A dictionary which maintains the insertion order of keys.
dataset/ETHPy150Open datastax/python-driver/cassandra/util.py/OrderedDict.__init__