如何修改Wordpress内置的wp_trim_words函数

function custom_trim_words( $text, $num_words = 55, $more = null ) {
    $original_text = $text;
    $text = wp_strip_all_tags( $text );
    $words_array = preg_split( "/[\n\r\t ]+/", $text, $num_words + 1, PREG_SPLIT_NO_EMPTY );
    if ( count( $words_array ) > $num_words ) {
        array_pop( $words_array );
        $text = implode( ' ', $words_array );
        $text .= $more;
    } else {
        $text = implode( ' ', $words_array );
    }
    /**
     * Filters the text content after words have been trimmed.
     *
     * @since 3.3.0
     *
     * @param string $text          The trimmed text.
     * @param int    $num_words     The number of words to trim the text to. Default 55.
     * @param string $more          An optional string to append to the end of the trimmed text, e.g. ….
     * @param string $original_text The text before it was trimmed.
     */
    return apply_filters( 'wp_trim_words', $text, $num_words, $more, $original_text );
}

<?php echo custom_trim_words( get_the_content(), 20, '...' ); ?>