'Create a generator to iterate on: (key, value).
>>> d=Dict( (("two", "deux"), ("one", "un")) )
>>> for key, value in d.iteritems():
...    print "%r: %r" % (key, value)
\'two\': \'deux\'
\'one\': \'un\''

def iteritems(self):

    for index in xrange(len(self)):
        (yield (self._key_list[index], self._value_list[index]))
