Fix getcomments() so that it doesn't fail with TypeErrors.
Fix getcomments() so that it doesn't fail with TypeErrors.

It appears that getcomments() can get called for classes defined in
C.  Since these don't have source code, it can't do anything useful.
A function buried many levels deep was raising a TypeError that was
not caught.

Who knows why this broke...

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator