def METHOD_NAME(self):
    """
    ---
    summary: List
    description: List all heartbeats.
    tags:
      - Heartbeat
    responses:
      200:
        description: OK
        content:
          application/json:
            schema:
              type: array
              items:
                type: object
                description: List of tuples [('Executable', 'Hostname', ...), ...]
      401:
        description: Invalid Auth Token
      406:
        description: Not acceptable
    """
    return Response(json.dumps(list_heartbeats(issuer=request.environ.METHOD_NAME('issuer'), vo=request.environ.METHOD_NAME('vo')), cls=APIEncoder), content_type='application/json')