code: def get_extra_kwargs(self):
          
          extra_kwargs = getattr(self.Meta, 'extra_kwargs', {})
  
          read_only_fields = getattr(self.Meta, 'read_only_fields', None)
          if read_only_fields is not None:
              for field_name in read_only_fields:
                  kwargs = extra_kwargs.get(field_name, {})
                  kwargs['read_only'] = True
                  extra_kwargs[field_name] = kwargs
  
          return extra_kwargs
docs: Return a dictionary mapping field names to a dictionary of
          additional keyword arguments.