docs: def update_type_lookups(self):
          """ Update type and typestring lookup dicts.
  
          Must be called once the ``types`` and ``python_type_strings``
          attributes are set so that ``type_to_typestring`` and
          ``typestring_to_type`` are constructed.
  
          .. versionadded:: 0.2
  
          Notes
          -----
          Subclasses need to call this function explicitly.
  
          """
          self.type_to_typestring = dict(zip(self.types,
                                             self.python_type_strings))
          self.typestring_to_type = dict(zip(self.python_type_strings,
                                             self.types))