unittest.py: what is TestResult.__repr__ ?

[Richard Harlos]

I'm not a Python programmer (at least, not yet ;)

I am, however, trying to port the unittest.py framework to another
language.  Of all the languages that this testing framework has been
ported to, I thought that Python would be the easiest for me to
decipher.  For the most part, it seems pretty straightforward, except
for...

I'm presently stuck in the TestResult class.  Though I've searched for
the meaning of "__repr__" in the Python22 documentation, I cannot find
it.

Please help me understand this this convention of using leading and/or
trailing underscores in Python.

Thanks in advance...

Richard