lay height of the avatar in pixels. Defaults to $size.
	 *     @type int          $width         Display width of the avatar in pixels. Defaults to $size.
	 *     @type bool         $force_default Whether to always show the default image, never the Gravatar.
	 *                                       Default false.
	 *     @type string       $rating        What rating to display avatars up to. Accepts:
	 *                                       - 'G' (suitable for all audiences)
	 *                                       - 'PG' (possibly offensive, usually for audiences 13 and above)
	 *                                       - 'R' (intended for adult audiences above 17)
	 *                                       - 'X' (even more mature than above)
	 *                                       Default is the value of the 'avatar_rating' option.
	 *     @type string       $scheme        URL scheme to use. See set_url_scheme() for accepted values.
	 *                                       Default null.
	 *     @type array|string $class         Array or string of additional classes to add to the img element.
	 *                                       Default null.
	 *     @type bool         $force_display Whether to always show the avatar - ignores the show_avatars option.
	 *                                       Default false.
	 *     @type string       $loading       Value for the `loading` attribute.
	 *                                       Default null.
	 *     @type string       $fetchpriority Value for the `fetchpriority` attribute.
	 *                                       Default null.
	 *     @type string       $decoding      Value for the `decoding` attribute.
	 *                                       Default null.
	 *     @type string       $extra_attr    HTML attributes to insert in the IMG element. Is not sanitized.
	 *                                       Default empty.
	 * }
	 * @return string|false `<img>` tag for the user's avatar. False on failure.
	 */
	function get_avatar( $id_or_email, $size = 96, $default_value = '', $alt = '', $args = null ) {
		$defaults = array(
			// get_avatar_data() args.
			'size'          => 96,
			'height'        => null,
			'width'         => null,
			'default'       => get_option( 'avatar_default', 'mystery' ),
			'force_default' => false,
			'rating'        => get_option( 'avatar_rating' ),
			'scheme'        => null,
			'alt'           => '',
			'class'         => null,
			'force_display' => false,
			'loading'       => null,
			'fetchpriority' => null,
			'decoding'      => null,
			'extra_attr'    => '',
		);

		if ( empty( $args ) ) {
			$args = array();
		}

		$args['size']    = (int) $size;
		$args['default'] = $default_value;
		$args['alt']     = $alt;

		$args = wp_parse_args( $args, $defaults );

		if ( empty( $args['height'] ) ) {
			$args['height'] = $args['size'];
		}
		if ( empty( $args['width'] ) ) {
			$args['width'] = $args['size'];
		}

		// Update args with loading optimized attributes.
		$loading_optimization_attr = wp_get_loading_optimization_attributes( 'img', $args, 'get_avatar' );

		$args = array_merge( $args, $loading_optimization_attr );

		if ( is_object( $id_or_email ) && isset( $id_or_email->comment_ID ) ) {
			$id_or_email = get_comment( $id_or_email );
		}

		/**
		 * Allows the HTML for a user's avatar to be returned early.
		 *
		 * Returning a non-null value will effectively short-circuit get_avatar(), passing
		 * the value through the {@see 'get_avatar'} filter and returning early.
		 *
		 * @since 4.2.0
		 *
		 * @param string|null $avatar      HTML for the user's avatar. Default null.
		 * @param mixed       $id_or_email The avatar to retrieve. Accepts a user ID, Gravatar MD5 hash,
		 *                                 user email, WP_User object, WP_Post object, or WP_Comment object.
		 * @param array       $args        Arguments passed to get_avatar_url(), after processing.
		 */
		$avatar = apply_filters( 'pre_get_avatar', null, $id_or_email, $args );

		if ( ! is_null( $avatar ) ) {
			/** This filter is documented in wp-includes/pluggable.php */
			return apply_filters( 'get_avatar', $avatar, $id_or_email, $args['size'], $args['default'], $args['alt'], $args );
		}

		if ( ! $args['force_display'] && ! get_option( 'show_avatars' ) ) {
			return false;
		}

		$url2x = get_avatar_url( $id_or_email, array_merge( $args, array( 'size' => $args['size'] * 2 ) ) );

		$args = get_avatar_data( $id_or_email, $args );

		$url = $args['url'];

		if ( ! $url || is_wp_error( $url ) ) {
			return false;
		}

		$class = array( 'avatar', 'avatar-' . (int) $args['size'], 'photo' );

		if ( ! $args['found_avatar'] || $args['force_default'] ) {
			$class[] = 'avatar-default';
		}

		if ( $args['class'] ) {
			if ( is_array( $args['class'] ) ) {
				$class = array_merge( $class, $args['class'] );
			} else {
				$class[] = $args['class'];
			}
		}

		// Add `loading`, `fetchpriority`, and `decoding` attributes.
		$extra_attr = $args['extra_attr'];

		if ( in_array( $args['loading'], array( 'lazy', 'eager' ), true )
			&& ! preg_match( '/\bloading\s*=/', $extra_attr )
		) {
			if ( ! empty( $extra_attr ) ) {
				$extra_attr .= ' ';
			}

			$extra_attr .= "loading='{$args['loading']}'";
		}

		if ( in_array( $args['fetchpriority'], array( 'high', 'low', 'auto' ), true )
			&& ! preg_match( '/\bfetchpriority\s*=/', $extra_attr )
		) {
			if ( ! empty( $extra_attr ) ) {
				$extra_attr .= ' ';
			}

			$extra_attr .= "fetchpriority='{$args['fetchpriority']}'";
		}

		if ( in_array( $args['decoding'], array( 'async', 'sync', 'auto' ), true )
			&& ! preg_match( '/\bdecoding\s*=/', $extra_attr )
		) {
			if ( ! empty( $extra_attr ) ) {
				$extra_attr .= ' ';
			}

			$extra_attr .= "decoding='{$args['decoding']}'";
		}

		$avatar = sprintf(
			"<img alt='%s' src='%s' srcset='%s' class='%s' height='%d' width='%d' %s/>",
			esc_attr( $args['alt'] ),
			esc_url( $url ),
			esc_url( $url2x ) . ' 2x',
			esc_attr( implode( ' ', $class ) ),
			(int) $args['height'],
			(int) $args['width'],
			$extra_attr
		);

		/**
		 * Filters the HTML for a user's avatar.
		 *
		 * @since 2.5.0
		 * @since 4.2.0 Added the `$args` parameter.
		 *
		 * @param string $avatar        HTML for the user's avatar.
		 * @param mixed  $id_or_email   The avatar to retrieve. Accepts a user ID, Gravatar MD5 hash,
		 *                              user email, WP_User object, WP_Post object, or WP_Comment object.
		 * @param int    $size          Height and width of the avatar in pixels.
		 * @param string $default_value URL for the default image or a default type. Accepts:
		 *                              - '404' (return a 404 instead of a default image)
		 *                              - 'retro' (a 8-bit arcade-style pixelated face)
		 *                              - 'robohash' (a robot)
		 *                              - 'monsterid' (a monster)
		 *                              - 'wavatar' (a cartoon face)
		 *                              - 'identicon' (the "quilt", a geometric pattern)
		 *                              - 'mystery', 'mm', or 'mysteryman' (The Oyster Man)
		 *                              - 'blank' (transparent GIF)
		 *                              - 'gravatar_default' (the Gravatar logo)
		 * @param string $alt           Alternative text to use in the avatar image tag.
		 * @param array  $args          Arguments passed to get_avatar_data(), after processing.
		 */
		return apply_filters( 'get_avatar', $avatar, $id_or_email, $args['size'], $args['default'], $args['alt'], $args );
	}
endif;

if ( ! function_exists( 'wp_text_diff' ) ) :
	/**
	 * Displays a human readable HTML representation of the difference between two strings.
	 *
	 * The Diff is available for getting the changes between versions. The output is
	 * HTML, so the primary use is for displaying the changes. If the two strings
	 * are equivalent, then an empty string will be returned.
	 *
	 * @since 2.6.0
	 *
	 * @see wp_parse_args() Used to change defaults to user defined settings.
	 * @uses Text_Diff
	 * @uses WP_Text_Diff_Renderer_Table
	 *
	 * @param string       $left_string  "old" (left) version of string.
	 * @param string       $right_string "new" (right) version of string.
	 * @param string|array $args {
	 *     Associative array of options to pass to WP_Text_Diff_Renderer_Table().
	 *
	 *     @type string $title           Titles the diff in a manner compatible
	 *                                   with the output. Default empty.
	 *     @type string $title_left      Change the HTML to the left of the title.
	 *                                   Default empty.
	 *     @type string $title_right     Change the HTML to the right of the title.
	 *                                   Default empty.
	 *     @type bool   $show_split_view True for split view (two columns), false for
	 *                                   un-split view (single column). Default true.
	 * }
	 * @return string Empty string if strings are equivalent or HTML with differences.
	 */
	function wp_text_diff( $left_string, $right_string, $args = null ) {
		$defaults = array(
			'title'           => '',
			'title_left'      => '',
			'title_right'     => '',
			'show_split_view' => true,
		);
		$args     = wp_parse_args( $args, $defaults );

		if ( ! class_exists( 'WP_Text_Diff_Renderer_Table', false ) ) {
			require ABSPATH . WPINC . '/wp-diff.php';
		}

		$left_string  = normalize_whitespace( $left_string );
		$right_string = normalize_whitespace( $right_string );

		$left_lines  = explode( "\n", $left_string );
		$right_lines = explode( "\n", $right_string );
		$text_diff   = new Text_Diff( $left_lines, $right_lines );
		$renderer    = new WP_Text_Diff_Renderer_Table( $args );
		$diff        = $renderer->render( $text_diff );

		if ( ! $diff ) {
			return '';
		}

		$is_split_view       = ! empty( $args['show_split_view'] );
		$is_split_view_class = $is_split_view ? ' is-split-view' : '';

		$r = "<table class='diff$is_split_view_class'>\n";

		if ( $args['title'] ) {
			$r .= "<caption class='diff-title'>$args[title]</caption>\n";
		}

		if ( $args['title_left'] || $args['title_right'] ) {
			$r .= '<thead>';
		}

		if ( $args['title_left'] || $args['title_right'] ) {
			$th_or_td_left  = empty( $args['title_left'] ) ? 'td' : 'th';
			$th_or_td_right = empty( $args['title_right'] ) ? 'td' : 'th';

			$r .= "<tr class='diff-sub-title'>\n";
			$r .= "\t<$th_or_td_left>$args[title_left]</$th_or_td_left>\n";
			if ( $is_split_view ) {
				$r .= "\t<$th_or_td_right>$args[title_right]</$th_or_td_right>\n";
			}
			$r .= "</tr>\n";
		}

		if ( $args['title_left'] || $args['title_right'] ) {
			$r .= "</thead>\n";
		}

		$r .= "<tbody>\n$diff\n</tbody>\n";
		$r .= '</table>';

		return $r;
	}
endif;