def markers_pass(self, req, extras=None):
extra_evals = (<EOL>req.marker.evaluate({'<STR_LIT>': extra})<EOL>for extra in self.get(req, ()) + (extras or (None,))<EOL>)<EOL>return not req.marker or any(extra_evals)<EOL>
Evaluate markers for req against each extra that
demanded it.

Return False if the req has a marker and fails
evaluation. Otherwise, return True.