Can't use a FlexEntity as the "kwargs" part of a call

[dobesv]

e.g.

>>> (lambda **args: args)(**FlexEntity(foo=1, bar=2))
Traceback (most recent call last):
  File "<input>", line 1, in <module>
TypeError: attribute of type 'NoneType' is not callable

The solution is to implement the keys() method:

>>> FlexEntity.keys = (lambda e: [key for key, value in e.iteritems()])
>>> (lambda **args: args)(**FlexEntity(foo=1, bar=2))
{'foo': 1, 'bar': 2}

[six8]

Interesting. I guess I never considered that you could make ** work for other classes. I just assumed it only worked with dict.