def get(self, action, default=None):
return self._action_sets.get(action, default)<EOL>
Return the action set, if any, associated with this action. If
        no action set is associated with this action, return the default.
        If no default is provided, None is used.

        Usage:
            action_set = match_set.get(action)

        Arguments:
            action: The action suggested by the desired ActionSet.
            default: The value returned if no such ActionSet exists. If no
                value is provided, None is used.