Pydev Code Completion for everything

As of PyDev 2.8.0 can use Sphinx or Epydoc comments for code completion: http://pydev.org/manual_adv_type_hints.html

[Edit]

Since PyDev 2.8.0, it can use docstrings and comments to discover the type of objects.

See: http://pydev.org/manual_adv_type_hints.html for details on the supported formats.

[Before PyDev 2.8.0]

Previously, it only supported assert isinstance calls (and this still works):

assert isinstance(a_list, list)

PyDev will be able to recognize it and properly provide code-completion for it (note that you can run Python without the assertions later on if you find it's making your code slower: What does Python optimization (-O or PYTHONOPTIMIZE) do? )

If you use PyCharm, you can pick either epydoc or sphinx docstring style and specify types of parameters and function return values according to that style (further discussion)