Distributing methods of a class across multiple files

[lh]

Is this possible please?  I have done some searching but it is hard to
narrow down Google searches to this question. What I would like to do
is, for example:
1) define a class Foo in file test.py... give it some methods
2) define a file test2.py which contains a set of methods that are
methods of class Foo defined in test.py.  I can import Foo obviously
but it isn't clear to me how to identify the methods in test2.py to be
methods of class Foo defined in test.py (normally I would just indent
them "def"'s under the class but the class isn't textually in
test2.py).

In short I would like to distribute code for one class across multiple
files so a given file doesn't get ridiculously long.

Thank you,
 Luke