docs: def delete_mappings_in_network(network_id, network_2_id=None, **kwargs):
      """
          Delete all the resource attribute mappings in a network. If another network
          is specified, only delete the mappings between the two networks.
      """
      qry = db.DBSession.query(ResourceAttrMap).filter(or_(ResourceAttrMap.network_a_id == network_id, ResourceAttrMap.network_b_id == network_id))
  
      if network_2_id is not None:
          qry = qry.filter(or_(ResourceAttrMap.network_a_id==network_2_id, ResourceAttrMap.network_b_id==network_2_id))
  
      mappings = qry.all()
  
      for m in mappings:
          db.DBSession.delete(m)
      db.DBSession.flush()
  
      return 'OK'