Python source cross reference doc generator?

[Harry Fuecks]

Hi All,

Wondering if a tool exists to generate "cross reference" documentation
for Python code bases?

Particularly after something like phpxref -
http://phpxref.sourceforge.net/ : written in Perl, scans a bunch of
PHP scripts and generates HTML output that allows you to see all the
classes / methods / functions / variables defined and (what I'm
interested in) where they are referenced. Essentially something like
API docs but with the addition of being able to see who's using a
particular method

Is there anything like this for Python? Have done much looking without success.

Many thanks.