'>>> d = OrderedDict(((1, 3), (3, 2), (2, 1)))
>>> c = OrderedDict(((0, 3), (3, 2), (2, 1)))
>>> c < d
True
>>> d < c
False
>>> d < dict(c)
Traceback (most recent call last):
TypeError: Can only compare with other OrderedDicts'

def __lt__(self, other):

    if (not isinstance(other, OrderedDict)):
        raise TypeError('Can    only    compare    with    other    OrderedDicts')
    return (self.items() < other.items())
