code: def scales(value):
          
          for i, entry in enumerate(value):
              _assert_is_type('scales[{0}]'.format(i), entry, Scale)
docs: list or KeyedList of ``Scale`` : Scale definitions
  
          Scales map the data from the domain of the data to some
          visualization space (such as an x-axis). See the :class:`Scale`
          class for details.