code: def cancel_milestone_payment(session, milestone_id):
      
      params_data = {
          'action': 'cancel',
      }
      # PUT /api/projects/0.1/milestones/{milestone_id}/?action=release
      endpoint = 'milestones/{}'.format(milestone_id)
      response = make_put_request(session, endpoint, params_data=params_data)
      json_data = response.json()
      if response.status_code == 200:
          return json_data['status']
      else:
          raise MilestoneNotCancelledException(
              message=json_data['message'],
              error_code=json_data['error_code'],
              request_id=json_data['request_id'])
docs: Release a milestone payment