docs: def to_python(self, value):
          """
          "Called during deserialization and during the clean() method used
          from forms.... [s]hould deal gracefully with... (*) an instance of
          the correct type; (*) a string; (*) None (if the field allows
          null=True)."
  
          "For ``to_python()``, if anything goes wrong during value conversion,
          you should raise a ``ValidationError`` exception."
          """
          if value is None:
              return value
          if not isinstance(value, str):
              return value
          try:
              return json_decode(value)
          except Exception as err:
              raise ValidationError(repr(err))