Disable Python optimizations for the frame.

def unoptimize_scope(self, frame):
        """Disable Python optimizations for the frame."""
        # XXX: this is not that nice but it has no real overhead.  It
        # mainly works because python finds the locals before dead code
        # is removed.  If that breaks we have to add a dummy function
        # that just accepts the arguments and does nothing.
        if frame.identifiers.declared:
            self.writeline('%sdummy(%s)' % (
                unoptimize_before_dead_code and 'if 0: ' or '',
                ', '.join('l_' + name for name in frame.identifiers.declared)
            ))