code: def create_permission_request(self, customer, pos_id, pos_tid, scope,
                                    ledger=None, text=None, callback_uri=None,
                                    expires_in=None):
          
          arguments = {'customer': customer,
                       'pos_id': pos_id,
                       'pos_tid': pos_tid,
                       'scope': scope,
                       'ledger': ledger,
                       'text': text,
                       'callback_uri': callback_uri,
                       'expires_in': expires_in}
          return self.do_req('POST',
                             self.merchant_api_base_url + '/permission_request/',
                             arguments).json()
docs: Create permission request
  
          The call is idempotent; that is, if one posts the same pos_id and
          pos_tid twice, only one Permission request is created.