( $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 The `$args` parameter was added.
		 *
		 * @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          Square avatar width and height in pixels to retrieve.
		 * @param string $default_value URL for the default image or a default type. Accepts '404', 'retro', 'monsterid',
		 *                              'wavatar', 'indenticon', 'mystery', 'mm', 'mysteryman', 'blank', or 'gravatar_default'.
		 * @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;