ction Should give context to what is taking place and be the same when nonce was created.
	 * @return int|false 1 if the nonce is valid and generated between 0-12 hours ago,
	 *                   2 if the nonce is valid and generated between 12-24 hours ago.
	 *                   False if the nonce is invalid.
	 */
	function wp_verify_nonce( $nonce, $action = -1 ) {
		$nonce = (string) $nonce;
		$user  = wp_get_current_user();
		$uid   = (int) $user->ID;
		if ( ! $uid ) {
			/**
			 * Filters whether the user who generated the nonce is logged out.
			 *
			 * @since 3.5.0
			 *
			 * @param int    $uid    ID of the nonce-owning user.
			 * @param string $action The nonce action.
			 */
			$uid = apply_filters( 'nonce_user_logged_out', $uid, $action );
		}

		if ( empty( $nonce ) ) {
			return false;
		}

		$token = wp_get_session_token();
		$i     = wp_nonce_tick();

		// Nonce generated 0-12 hours ago.
		$expected = substr( wp_hash( $i . '|' . $action . '|' . $uid . '|' . $token, 'nonce' ), -12, 10 );
		if ( hash_equals( $expected, $nonce ) ) {
			return 1;
		}

		// Nonce generated 12-24 hours ago.
		$expected = substr( wp_hash( ( $i - 1 ) . '|' . $action . '|' . $uid . '|' . $token, 'nonce' ), -12, 10 );
		if ( hash_equals( $expected, $nonce ) ) {
			return 2;
		}

		/**
		 * Fires when nonce verification fails.
		 *
		 * @since 4.4.0
		 *
		 * @param string     $nonce  The invalid nonce.
		 * @param string|int $action The nonce action.
		 * @param WP_User    $user   The current user object.
		 * @param string     $token  The user's session token.
		 */
		do_action( 'wp_verify_nonce_failed', $nonce, $action, $user, $token );

		// Invalid nonce.
		return false;
	}
endif;

if ( ! function_exists( 'wp_create_nonce' ) ) :
	/**
	 * Creates a cryptographic token tied to a specific action, user, user session,
	 * and window of time.
	 *
	 * @since 2.0.3
	 * @since 4.0.0 Session tokens were integrated with nonce creation
	 *
	 * @param string|int $action Scalar value to add context to the nonce.
	 * @return string The token.
	 */
	function wp_create_nonce( $action = -1 ) {
		$user = wp_get_current_user();
		$uid  = (int) $user->ID;
		if ( ! $uid ) {
			/** This filter is documented in wp-includes/pluggable.php */
			$uid = apply_filters( 'nonce_user_logged_out', $uid, $action );
		}

		$token = wp_get_session_token();
		$i     = wp_nonce_tick();

		return substr( wp_hash( $i . '|' . $action . '|' . $uid . '|' . $token, 'nonce' ), -12, 10 );
	}
endif;

if ( ! function_exists( 'wp_salt' ) ) :
	/**
	 * Returns a salt to add to hashes.
	 *
	 * Salts are created using secret keys. Secret keys are located in two places:
	 * in the database and in the wp-config.php file. The secret key in the database
	 * is randomly generated and will be appended to the secret keys in wp-config.php.
	 *
	 * The secret keys in wp-config.php should be updated to strong, random keys to maximize
	 * security. Below is an example of how the secret key constants are defined.
	 * Do not paste this example directly into wp-config.php. Instead, have a
	 * {@link https://api.wordpress.org/secret-key/1.1/salt/ secret key created} just
	 * for you.
	 *
	 *     define('AUTH_KEY',         ' Xakm<o xQy rw4EMsLKM-?!T+,PFF})H4lzcW57AF0U@N@< >M%G4Yt>f`z]MON');
	 *     define('SECURE_AUTH_KEY',  'LzJ}op]mr|6+![P}Ak:uNdJCJZd>(Hx.-Mh#Tz)pCIU#uGEnfFz|f ;;eU%/U^O~');
	 *     define('LOGGED_IN_KEY',    '|i|Ux`9<p-h$aFf(qnT:sDO:D1P^wZ$$/Ra@miTJi9G;ddp_<q}6H1)o|a +&JCM');
	 *     define('NONCE_KEY',        '%:R{[P|,s.KuMltH5}cI;/k<Gx~j!f0I)m_sIyu+&NJZ)-iO>z7X>QYR0Z_XnZ@|');
	 *     define('AUTH_SALT',        'eZyT)-Naw]F8CwA*VaW#q*|.)g@o}||wf~@C-YSt}(dh_r6EbI#A,y|nU2{B#JBW');
	 *     define('SECURE_AUTH_SALT', '!=oLUTXh,QW=H `}`L|9/^4-3 STz},T(w}W<I`.JjPi)<Bmf1v,HpGe}T1:Xt7n');
	 *     define('LOGGED_IN_SALT',   '+XSqHc;@Q*K_b|Z?NC[3H!!EONbh.n<+=uKR:>*c(u`g~EJBf#8u#R{mUEZrozmm');
	 *     define('NONCE_SALT',       'h`GXHhD>SLWVfg1(1(N{;.V!MoE(SfbA_ksP@&`+AycHcAV$+?@3q+rxV{%^VyKT');
	 *
	 * Salting passwords helps against tools which has stored hashed values of
	 * common dictionary strings. The added values makes it harder to crack.
	 *
	 * @since 2.5.0
	 *
	 * @link https://api.wordpress.org/secret-key/1.1/salt/ Create secrets for wp-config.php
	 *
	 * @param string $scheme Authentication scheme (auth, secure_auth, logged_in, nonce)
	 * @return string Salt value
	 */
	function wp_salt( $scheme = 'auth' ) {
		static $cached_salts = array();
		if ( isset( $cached_salts[ $scheme ] ) ) {
			/**
			 * Filters the WordPress salt.
			 *
			 * @since 2.5.0
			 *
			 * @param string $cached_salt Cached salt for the given scheme.
			 * @param string $scheme      Authentication scheme. Values include 'auth',
			 *                            'secure_auth', 'logged_in', and 'nonce'.
			 */
			return apply_filters( 'salt', $cached_salts[ $scheme ], $scheme );
		}

		static $duplicated_keys;
		if ( null === $duplicated_keys ) {
			$duplicated_keys = array( 'put your unique phrase here' => true );
			foreach ( array( 'AUTH', 'SECURE_AUTH', 'LOGGED_IN', 'NONCE', 'SECRET' ) as $first ) {
				foreach ( array( 'KEY', 'SALT' ) as $second ) {
					if ( ! defined( "{$first}_{$second}" ) ) {
						continue;
					}
					$value                     = constant( "{$first}_{$second}" );
					$duplicated_keys[ $value ] = isset( $duplicated_keys[ $value ] );
				}
			}
		}

		$values = array(
			'key'  => '',
			'salt' => '',
		);
		if ( defined( 'SECRET_KEY' ) && SECRET_KEY && empty( $duplicated_keys[ SECRET_KEY ] ) ) {
			$values['key'] = SECRET_KEY;
		}
		if ( 'auth' === $scheme && defined( 'SECRET_SALT' ) && SECRET_SALT && empty( $duplicated_keys[ SECRET_SALT ] ) ) {
			$values['salt'] = SECRET_SALT;
		}

		if ( in_array( $scheme, array( 'auth', 'secure_auth', 'logged_in', 'nonce' ), true ) ) {
			foreach ( array( 'key', 'salt' ) as $type ) {
				$const = strtoupper( "{$scheme}_{$type}" );
				if ( defined( $const ) && constant( $const ) && empty( $duplicated_keys[ constant( $const ) ] ) ) {
					$values[ $type ] = constant( $const );
				} elseif ( ! $values[ $type ] ) {
					$values[ $type ] = get_site_option( "{$scheme}_{$type}" );
					if ( ! $values[ $type ] ) {
						$values[ $type ] = wp_generate_password( 64, true, true );
						update_site_option( "{$scheme}_{$type}", $values[ $type ] );
					}
				}
			}
		} else {
			if ( ! $values['key'] ) {
				$values['key'] = get_site_option( 'secret_key' );
				if ( ! $values['key'] ) {
					$values['key'] = wp_generate_password( 64, true, true );
					update_site_option( 'secret_key', $values['key'] );
				}
			}
			$values['salt'] = hash_hmac( 'md5', $scheme, $values['key'] );
		}

		$cached_salts[ $scheme ] = $values['key'] . $values['salt'];

		/** This filter is documented in wp-includes/pluggable.php */
		return apply_filters( 'salt', $cached_salts[ $scheme ], $scheme );
	}
endif;

if ( ! function_exists( 'wp_hash' ) ) :
	/**
	 * Get hash of given string.
	 *
	 * @since 2.0.3
	 *
	 * @param string $data   Plain text to hash
	 * @param string $scheme Authentication scheme (auth, secure_auth, logged_in, nonce)
	 * @return string Hash of $data
	 */
	function wp_hash( $data, $scheme = 'auth' ) {
		$salt = wp_salt( $scheme );

		return hash_hmac( 'md5', $data, $salt );
	}
endif;

if ( ! function_exists( 'wp_hash_password' ) ) :
	/**
	 * Create a hash (encrypt) of a plain text password.
	 *
	 * For integration with other applications, this function can be overwritten to
	 * instead use the other package password checking algorithm.
	 *
	 * @since 2.5.0
	 *
	 * @global PasswordHash $wp_hasher PHPass object
	 *
	 * @param string $password Plain text user password to hash
	 * @return string The hash string of the password
	 */
	function wp_hash_password( $password ) {
		global $wp_hasher;

		if ( empty( $wp_hasher ) ) {
			require_once ABSPATH . WPINC . '/class-phpass.php';
			// By default, use the portable hash from phpass.
			$wp_hasher = new PasswordHash( 8, true );
		}

		return $wp_hasher->HashPassword( trim( $password ) );
	}
endif;

if ( ! function_exists( 'wp_check_password' ) ) :
	/**
	 * Checks the plaintext password against the encrypted Password.
	 *
	 * Maintains compatibility between old version and the new cookie authentication
	 * protocol using PHPass library. The $hash parameter is the encrypted password
	 * and the function compares the plain text password when encrypted similarly
	 * against the already encrypted password to see if they match.
	 *
	 * For integration with other applications, this function can be overwritten to
	 * instead use the other package password checking algorithm.
	 *
	 * @since 2.5.0
	 *
	 * @global PasswordHash $wp_hasher PHPass object used for checking the password
	 *                                 against the $hash + $password
	 * @uses PasswordHash::CheckPassword
	 *
	 * @param string     $password Plaintext user's password
	 * @param string     $hash     Hash of the user's password to check against.
	 * @param string|int $user_id  Optional. User ID.
	 * @return bool False, if the $password does not match the hashed password
	 */
	function wp_check_password( $password, $hash, $user_id = '' ) {
		global $wp_hasher;

		// If the hash is still md5...
		if ( strlen( $hash ) <= 32 ) {
			$check = hash_equals( $hash, md5( $password ) );
			if ( $check && $user_id ) {
				// Rehash using new hash.
				wp_set_password( $password, $user_id );
				$hash = wp_hash_password( $password );
			}

			/**
			 * Filters whether the plaintext password matches the encrypted password.
			 *
			 * @since 2.5.0
			 *
			 * @param bool       $check    Whether the passwords match.
			 * @param string     $password The plaintext password.
			 * @param string     $hash     The hashed password.
			 * @param string|int $user_id  User ID. Can be empty.
			 */
			return apply_filters( 'check_password', $check, $password, $hash, $user_id );
		}

		// If the stored hash is longer than an MD5,
		// presume the new style phpass portable hash.
		if ( empty( $wp_hasher ) ) {
			require_once ABSPATH . WPINC . '/class-phpass.php';
			// By default, use the portable hash from phpass.
			$wp_hasher = new PasswordHash( 8, true );
		}

		$check = $wp_hasher->CheckPassword( $password, $hash );

		/** This filter is documented in wp-includes/pluggable.php */
		return apply_filters( 'check_password', $check, $password, $hash, $user_id );
	}
endif;

if ( ! function_exists( 'wp_generate_password' ) ) :
	/**
	 * Generates a random password drawn from the defined set of characters.
	 *
	 * Uses wp_rand() is used to create passwords with far less predictability
	 * than similar native PHP functions like `rand()` or `mt_rand()`.
	 *
	 * @since 2.5.0
	 *
	 * @param int  $length              Optional. The length of password to generate. Default 12.
	 * @param bool $special_chars       Optional. Whether to include standard special characters.
	 *                                  Default true.
	 * @param bool $extra_special_chars Optional. Whether to include other special characters.
	 *                                  Used when generating secret keys and salts. Default false.
	 * @return string The random password.
	 */
	function wp_generate_password( $length = 12, $special_chars = true, $extra_special_chars = false ) {
		$chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
		if ( $special_chars ) {
			$chars .= '!@#$%^&*()';
		}
		if ( $extra_special_chars ) {
			$chars .= '-_ []{}<>~`+=,.;:/?|';
		}

		$password = '';
		for ( $i = 0; $i < $length; $i++ ) {
			$password .= substr( $chars, wp_rand( 0, strlen( $chars ) - 1 ), 1 );
		}

		/**
		 * Filters the randomly-generated password.
		 *
		 * @since 3.0.0
		 * @since 5.3.0 Added the `$length`, `$special_chars`, and `$extra_special_chars` parameters.
		 *
		 * @param string $password            The generated password.
		 * @param int    $length              The length of password to generate.
		 * @param bool   $special_chars       Whether to include standard special characters.
		 * @param bool   $extra_special_chars Whether to include other special characters.
		 */
		return apply_filters( 'random_password', $password, $length, $special_chars, $extra_special_chars );
	}
endif;

if ( ! function_exists( 'wp_rand' ) ) :
	/**
	 * Generates a random number.
	 *
	 * @since 2.6.2
	 * @since 4.4.0 Uses PHP7 random_int() or the random_compat library if available.
	 *
	 * @global string $rnd_value
	 *
	 * @param int $min Lower limit for the generated number
	 * @param int $max Upper limit for the generated number
	 * @return int A random number between min and max
	 */
	function wp_rand( $min = 0, $max = 0 ) {
		global $rnd_value;

		// Some misconfigured 32-bit environments (Entropy PHP, for example)
		// truncate integers larger than PHP_INT_MAX to PHP_INT_MAX rather than overflowing them to floats.
		$max_random_number = 3000000000 === 2147483647 ? (float) '4294967295' : 4294967295; // 4294967295 = 0xffffffff

		// We only handle ints, floats are truncated to their integer value.
		$min = (int) $min;
		$max = (int) $max;

		// Use PHP's CSPRNG, or a compatible method.
		static $use_random_int_functionality = true;
		if ( $use_random_int_functionality ) {
			try {
				$_max = ( 0 != $max ) ? $max : $max_random_number;
				// wp_rand() can accept arguments in either order, PHP cannot.
				$_max = max( $min, $_max );
				$_min = min( $min, $_max );
				$val  = random_int( $_min, $_max );
				if ( false !== $val ) {
					return absint( $val );
				} else {
					$use_random_int_functionality = false;
				}
			} catch ( Error $e ) {
				$use_random_int_functionality = false;
			} catch ( Exception $e ) {
				$use_random_int_functionality = false;
			}
		}

		// Reset $rnd_value after 14 uses.
		// 32 (md5) + 40 (sha1) + 40 (sha1) / 8 = 14 random numbers from $rnd_value.
		if ( strlen( $rnd_value ) < 8 ) {
			if ( defined( 'WP_SETUP_CONFIG' ) ) {
				static $seed = '';
			} else {
				$seed = get_transient( 'random_seed' );
			}
			$rnd_value  = md5( uniqid( microtime() . mt_rand(), true ) . $seed );
			$rnd_value .= sha1( $rnd_value );
			$rnd_value .= sha1( $rnd_value . $seed );
			$seed       = md5( $seed . $rnd_value );
			if ( ! defined( 'WP_SETUP_CONFIG' ) && ! defined( 'WP_INSTALLING' ) ) {
				set_transient( 'random_seed', $seed );
			}
		}

		// Take the first 8 digits for our value.
		$value = substr( $rnd_value, 0, 8 );

		// Strip the first eight, leaving the remainder for the next call to wp_rand().
		$rnd_value = substr( $rnd_value, 8 );

		$value = abs( hexdec( $value ) );

		// Reduce the value to be within the min - max range.
		if ( 0 != $max ) {
			$value = $min + ( $max - $min + 1 ) * $value / ( $max_random_number + 1 );
		}

		return abs( (int) $value );
	}
endif;

if ( ! function_exists( 'wp_set_password' ) ) :
	/**
	 * Updates the user's password with a new encrypted one.
	 *
	 * For integration with other applications, this function can be overwritten to
	 * instead use the other package password checking algorithm.
	 *
	 * Please note: This function should be used sparingly and is really only meant for single-time
	 * application. Leveraging this improperly in a plugin or theme could result in an endless loop
	 * of password resets if precautions are not taken to ensure it does not execute on every page load.
	 *
	 * @since 2.5.0
	 *
	 * @global wpdb $wpdb WordPress database abstraction object.
	 *
	 * @param string $password The plaintext new user password
	 * @param int    $user_id  User ID
	 */
	function wp_set_password( $password, $user_id ) {
		global $wpdb;

		$hash = wp_hash_password( $password );
		$wpdb->update(
			$wpdb->users,
			array(
				'user_pass'           => $hash,
				'user_activation_key' => '',
			),
			array( 'ID' => $user_id )
		);

		clean_user_cache( $user_id );
	}
endif;

if ( ! function_exists( 'get_avatar' ) ) :
	/**
	 * Retrieve the avatar `<img>` tag for a user, email address, MD5 hash, comment, or post.
	 *
	 * @since 2.5.0
	 * @since 4.2.0 Optional `$args` parameter added.
	 *
	 * @param mixed  $id_or_email The Gravatar to retrieve. Accepts a user_id, gravatar md5 hash,
	 *                            user email, WP_User object, WP_Post object, or WP_Comment object.
	 * @param int    $size        Optional. Height and width of the avatar image file in pixels. Default 96.
	 * @param string $default     Optional. URL for the default image or a default type. Accepts '404'
	 *                            (return a 404 instead of a default image), 'retro' (8bit), 'monsterid'
	 *                            (monster), 'wavatar' (cartoon face), 'indenticon' (the "quilt"),
	 *                            'mystery', 'mm', or 'mysteryman' (The Oyster Man), 'blank' (transparent GIF),
	 *                            or 'gravatar_default' (the Gravatar logo). Default is the value of the
	 *                            'avatar_default' option, with a fallback of 'mystery'.
	 * @param string $alt         Optional. Alternative text to use in img tag. Default empty.
	 * @param array  $args {
	 *     Optional. Extra arguments to retrieve the avatar.
	 *
	 *     @type int          $height        Display 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', 'PG', 'R', 'X', and are
	 *                                       judged in that order. 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       $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 = '', $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,
			'extra_attr'    => '',
		);

		if ( wp_lazy_loading_enabled( 'img', 'get_avatar' ) ) {
			$defaults['loading'] = wp_get_loading_attr_default( 'get_avatar' );
		}

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

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

		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` attribute.
		$extra_attr = $args['extra_attr'];
		$loading    = $args['loading'];

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

			$extra_attr .= "loading='{$loading}'";
		}

		$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 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     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;