public function format_datetime( $timestamp, $convert_to_utc = false, $convert_to_gmt = false ) {
		if ( $convert_to_gmt ) {
			if ( is_numeric( $timestamp ) ) {
				$timestamp = date( 'Y-m-d H:i:s', $timestamp );
			}

			$timestamp = get_gmt_from_date( $timestamp );
		}

		if ( $convert_to_utc ) {
			$timezone = new DateTimeZone( wc_timezone_string() );
		} else {
			$timezone = new DateTimeZone( 'UTC' );
		}

		try {

			if ( is_numeric( $timestamp ) ) {
				$date = new DateTime( "@{$timestamp}" );
			} else {
				$date = new DateTime( $timestamp, $timezone );
			}

			// convert to UTC by adjusting the time based on the offset of the site's timezone
			if ( $convert_to_utc ) {
				$date->modify( -1 * $date->getOffset() . ' seconds' );
			}
		} catch ( Exception $e ) {

			$date = new DateTime( '@0' );
		}

		return $date->format( 'Y-m-d\TH:i:s\Z' );
	}