private function psr4_get_file_name_from_class( $class ) {
		$class = strtolower( $class );
		if ( stristr( $class, '\\' ) ) {

			// If the first item is == the collection name, trim it off.
			$class = str_ireplace( static::$autoload_class_prefix, '', $class );

			// Maybe fix formatting underscores to dashes and double to single slashes.
			$class     = str_replace( [ '_', '\\' ], [ '-', '/' ], $class );
			$class     = explode( '/', $class );
			$file_name = &$class[ count( $class ) - 1 ];
			$file_name = static::$filename_prefix . $file_name . '.php';
			$file_path = join( DIRECTORY_SEPARATOR, $class );

			return $file_path;
		} else {
			return static::$filename_prefix . str_replace( '_', '-', $class ) . '.php';
		}
	}