title: Gulp Glob Error on Src()
body: <p>I'm banging my head with what should be a simple fix to a gulpfile that would allow it to build scss files.</p>
  
  <p>I have the following structure in my angular2 project:
  <code>
  |-rootDir
  |-- app
  |--- &lt;bunch of stuff in the app dir&gt;
  |-- resources
  |--- scss
  |---- &lt;scss files&gt;
  </code></p>
  
  <p>However, whenever I run <code>gulp create</code>I get an error stating <code>Error: Invalid glob argument: undefined</code></p>
  
  <p>What am I doing wrong here???</p>
  
  <p>This is my gulpfile:</p>
  
  <pre><code>var gulp = require('gulp'),
  sass = require('gulp-sass'),
  minifycss = require('gulp-minify-css'),
  autoprefixer = require('gulp-autoprefixer'),
  concat = require('gulp-concat'),
  debug = require('gulp-debug'),
  del = require('del'),
  insert = require('gulp-insert'),
  fs = require("fs");
  
  /* Tasks Functions */
  sass = function(files, dest) {
      pipe_files = gulp.src(files);
  
      return pipe_files
          .pipe(debug())
          .pipe(sass().on('error', sass.logError))
          .pipe(autoprefixer('last 2 version', 'safari 5', 'ie 8', 'ie 9', 'opera 12.1', 'ios 6', 'android 4'))
          .pipe(minifycss())
          .pipe(gulp.dest(dest));
  }
  
  /* CSS Tasks */
  gulp.task( 'styles', function() { sass( ['./resources/scss/*.scss'], './resources/css_gulp/') });
  
  gulp.task('clean', function(cb) {
      del(['./resources/css_gulp/*.*'], cb)
  });
  
  gulp.task( 'create', function() {
      gulp.start('styles');
  });
  
  gulp.task('default', ['clean'], function() {
      gulp.start('create');
  });
  </code></pre>
  
  <p>So, where am I going wrong on the paths?</p>
  
  <p><strong>* EDIT *</strong>
  I've added gulp-debug and this is the output:
  <code>[20:03:40] Finished 'create' after 17 ms
  [20:03:40] gulp-debug: resources/scss/main.scss
  [20:03:40] gulp-debug: resources/scss/prime-overrides.scss
  [20:03:40] gulp-debug: 2 items</code></p>
  
  <p>Everything seems correct here. So why the error?</p>