'Verifies that the action is valid on the target in this context.
:param context: Heat request context
:param action: String representing the action to be checked
:param target: Dictionary representing the object of the action.
:raises: self.exc (defaults to heat.common.exception.Forbidden)
:returns: A non-False value if access is allowed.'

def enforce(self, context, action, scope=None, target=None):

    _action = ('%s:%s' % ((scope or self.scope), action))
    _target = (target or {})
    return self._check(context, _action, _target, self.exc, action=action)
