WP_Widget::_register_one( int $number = -1 )

567	public function _register_one( $number = -1 ) {568		wp_register_sidebar_widget(569			$this->id,570			$this->name,571			$this->_get_display_callback(),572			$this->widget_options,573			array( 'number' => $number )574		);575 576		_register_widget_update_callback(577			$this->id_base,578			$this->_get_update_callback(),579			$this->control_options,580			array( 'number' => -1 )581		);582 583		_register_widget_form_callback(584			$this->id,585			$this->name,586			$this->_get_form_callback(),587			$this->control_options,588			array( 'number' => $number )589		);590	}