Add an unbound method to a class (Python 2)

util.py

from types import MethodType

LAMBDA_NAME = '<lambda>'

def extend(cls, method, name=None):
    method_name = method.__name__
    if method_name == LAMBDA_NAME and name is None:
        raise NameError('Please provide a usable name for a lambda method')
    elif name is not None:
        method_name = name
    setattr(cls, method_name, MethodType(method, None, cls))
    
class X(object):
    pass

x = X()
x.meow() # This fails
extend(X, lambda self: 5, 'meow')
x.meow() # returns 5 :)