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.

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