code: def _set_child_joined_alias_using_join_map(child, join_map, alias_map):
          
          for lhs, table, join_cols in join_map:
              if lhs is None:
                  continue
              if lhs == child.alias:
                  relevant_alias = child.related_alias
              elif lhs == child.related_alias:
                  relevant_alias = child.alias
              else:
                  continue
  
              join_info = alias_map[relevant_alias]
              if join_info.join_type is None:
                  continue
  
              if join_info.lhs_alias in [child.alias, child.related_alias]:
                  child.set_joined_alias(relevant_alias)
                  break
docs: Set the joined alias on the child, for Django <= 1.7.x.
          :param child:
          :param join_map:
          :param alias_map: