code: def persist_curves(self, asset_manager_id, business_date, curves, update_existing_curves=True):
          
          self.logger.info('Persist curves - Asset Manager: %s - Business Date: %s', asset_manager_id, business_date)
          url = '%s/curves/%s/%s' % (self.endpoint, asset_manager_id, business_date.isoformat())
          params = {'update_existing_curves': update_existing_curves}
          curves_json = [curve.to_interface() for curve in curves]
          response = self.session.post(url, params = params, json=curves_json)
          if response.ok:
              curves = [json_to_curve(curve) for curve in response.json()]
              return curves
          else:
              self.logger.error(response.text)
              response.raise_for_status()
docs: :param asset_manager_id:
          :param business_date:
          :param curves:
          :param update_existing_rates:
          :return: