docs: def set_attribute_mapping(resource_attr_a, resource_attr_b, **kwargs):
      """
          Define one resource attribute from one network as being the same as
          that from another network.
      """
      user_id = kwargs.get('user_id')
      ra_1 = get_resource_attribute(resource_attr_a)
      ra_2 = get_resource_attribute(resource_attr_b)
  
      mapping = ResourceAttrMap(resource_attr_id_a = resource_attr_a,
                               resource_attr_id_b  = resource_attr_b,
                               network_a_id     = ra_1.get_network().id,
                               network_b_id     = ra_2.get_network().id )
  
      db.DBSession.add(mapping)
  
      db.DBSession.flush()
  
      return mapping