docs: def formfield(self, **kwargs):
          """
          :returns: A :class:`~osm_field.forms.OSMFormField` with a
              :class:`~osm_field.widgets.OSMWidget`.
          """
          widget_kwargs = {
              'lat_field': self.latitude_field_name,
              'lon_field': self.longitude_field_name,
          }
  
          if self.data_field_name:
              widget_kwargs['data_field'] = self.data_field_name
  
          defaults = {
              'form_class': OSMFormField,
              'widget': OSMWidget(**widget_kwargs),
          }
          defaults.update(kwargs)
  
          return super(OSMField, self).formfield(**defaults)