First note, this is over 80 chars.  As far as formatting goes, I generally suggest people to read the [Google Python Style Guide](http://google-styleguide.googlecode.com/svn/trunk/pyguide.html?showone=Line_length#Line_length), it spells things out very well and has useful examples.

Second, looking at this, I feel like the break pattern is nicer.  So, basically, kill `continue_processing` and just do `while True:`.  Then this condition becomes:

```py
        if (not tasks_processed or
                (max_iterations and iterations >= max_iterations)):
            break
```

We can do the assignment, but it isn't clear to me that it buys us anything.  We always want at least one pass through the loop, and you're just assigning to the conditional then immediately checking it, and you're not saving line length.