code: def stringify(type_name, value, **opts):
      
      type_name, opts = _field_options(type_name, opts)
      return converter(type_name).stringify(value, **opts)
docs: Generate a string representation of the data in ``value``.
  
      Based on the converter specified by ``type_name``. This is
      guaranteed to yield a form which can easily be parsed by ``cast()``.