public function markEmailRead( $email_id = null ) {
		if ( ! $email_id ) {
			$this->assertNotEmpty( $this->_current_email, 'The current email is not selected' );
			$email_id = $this->_current_email['id'];
		}

		$this->_send_patch_request( '/messages/' . $email_id, array(
			'message' => array( 'is_read' => true )
		) );
	}