def _compute(self):
r = self<EOL>for func, args, kwargs in self._todo:<EOL><INDENT>r = func(self)(*args, **kwargs)<EOL><DEDENT>return r<EOL>
Execute the style functions built up in `self._todo`.

Relies on the conventions that all style functions go through
.apply or .applymap. The append styles to apply as tuples of

(application method, *args, **kwargs)