star unpacking for own classes
The exception message:
argument after * must be a sequence
should really say, argument after * must be an iterable.
Often star-unpacking is called "iterable unpacking" for this reason. See PEP 448 (Additional Unpacking Generalizations) and PEP 3132 (Extended Iterable Unpacking).
Edit: Looks like this has been fixed for python 3.5.2 and 3.6. In future it will say:
argument after * must be an iterable
In order to have star unpack, your class must be an iterable i.e. it must define an __iter__ that returns an iterator:
class Agent(object): def __init__(self, cards): self.cards = cards def __len__(self): return len(self.cards) def __iter__(self): return (card for card in self.cards)then:
In [11]: a = Agent([1, 2, 3, 4])In [12]: print(*a) # Note: in python 2 this will print the tuple1 2 3 4