docs: def select(self, attr, default=None):
          """
          Select a given attribute (or chain or attributes) from the objects within the
          list.
  
          Args:
              attr (str): attributes to be selected (with initial `.` omitted)
              default (any): value to return if given element in list doesn't contain
                  desired attribute
  
          Returns:
              nhl.List: list of selected attribute values
          """
          return List([_select(item, attr, default) for item in self])