<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def list_policies(self, scaling_group):
 """ Returns a list of all policies defined for the specified scaling group. """

        uri = "/%s/%s/policies" % (self.uri_base, utils.get_id(scaling_group))
        resp, resp_body = self.api.method_get(uri)
        return [AutoScalePolicy(self, data, scaling_group)
                for data in resp_body.get("policies", [])]