PyCharm: How to document :rtype: for function that returns generator

Question

I try to document a :rtype: docstring parameter returning a generator of Node:

def __iter__(self):
    """iterate over node children

    :rtype: ???
    """
    for node in self.children.itervalues():
        yield node

What :rtype: is supposed to be? generator of Node doesn't seems to work.

Answer 1

You can hint the type of self.children using :type below it, as described in the official documentation. This would let you work with this variable everywhere using defined types. Here is an example:

class Node(object):
    def foo(self):
        pass


class Iterator(object):
    def __init__(self):
        self.children = ''
        """:type: dict[str, Node]"""   # <<< define type of self.children after assigning the value

    def __iter__(self):
        for node in self.children.itervalues():
            yield node


if __name__ == '__main__':
    for node in Iterator():
        node. # <<< type hinting will work here

But if you prefer to set the return type of __iter__ method, you can do it using next syntax:

def __iter__(self):
    """
    :rtype: collections.Iterable[Node]
    """
    for node in self.children.itervalues():
        yield node

I would prefer first solution though.