How to use the sass.js.writeFile function in sass

Q.all(files.map(function (file) {
			var deferred = Q.defer();
			var src = file.src[0];
			Sass.writeFile(src, grunt.file.read(src));
			if (PATH.basename(src)[0] !== '_') {
				Sass.compileFile(src, function (result) {
					if  (result.status !== 0) {
						grunt.log.error(result.formatted + '\n');
						grunt.warn('');
						deferred.reject();
					} else {
						try {
							var cssFullPath = file.dest;
							var content = result.text;
							if (data.sourceMap && result.map) {
								var cssFile = PATH.basename(cssFullPath);
								content = "/*# sourceMappingURL=" + cssFile + ".map */\n" + content;
								var rootDirectory = "sass/" + PATH.dirname(src);
								result.map.file = cssFile;
								result.map.sources = result.map.sources.map(function (source) {