def add_policy(self, policy_json):
        '''**Description**
            Add a new policy using the provided json.

        **Arguments**
            - policy_json: a description of the new policy

        **Success Return Value**
            The string "OK"

        **Example**
            `examples/add_policy.py <https://github.com/draios/python-sdc-client/blob/master/examples/add_policy.py>`_

        '''

        try:
            policy_obj = json.loads(policy_json)
        except Exception as e:
            return [False, "policy json is not valid json: {}".format(str(e))]

        body = {"policy": policy_obj}
        res = requests.post(self.url + '/api/policies', headers=self.hdrs, data=json.dumps(body), verify=self.ssl_verify)
        return self._request_result(res)