docs: def apply_widget_template(self, field_name):
          """
          Applies widget template overrides if available.
  
          The method uses the `get_widget_template` method to determine if the widget
          template should be exchanged. If a template is available, the template_name
          property of the widget instance is updated.
  
          :param field_name: A field name of the form.
          """
          field = self.fields[field_name]
          template_name = self.get_widget_template(field_name, field)
  
          if template_name:
              field.widget.template_name = template_name