<p>I can't tell from the Python documentation whether the re.compile(x) function may throw an exception (assuming you pass in a string). I imagine there is something that could be considered an invalid regular expression. The larger question is, where do I go to find if a given Python library call may throw exception(s) and what those are? </p>

Well,
```
re.compile
```
certainly may:
```
```
>>> import re
>>> re.compile('he(lo')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Python25\lib\re.py", line 180, in compile
    return _compile(pattern, flags)
  File "C:\Python25\lib\re.py", line 233, in _compile
    raise error, v # invalid expression
sre_constants.error: unbalanced parenthesis
```
```
The documentation
does support this, in a roundabout way - check the bottom of the "Module Contents" page for (brief) description of the
```
error
```
exception.
Unfortunately, I don't have any answer to the general question. I suppose the documentation for the various modules varies in quality and thoroughness. If there were particular modules you were interested in, you might be able to
decompile
them (if written in Python) or even
look at the source
, if they're in the standard library.