title: python / os.listdir/ reading subfodlers
body: <p>Using python 3.5 on OSX
  There are 5 subfolders in '/Users/abs/Desktop/data' and I am trying to look all the subfolders. But i got an error NotADirectoryError: [Errno 20] Not a directory: '/Users/abs/Desktop/data/.DS_Store'
  How do I fix this problem</p>
  
  <pre><code>data_path = '/Users/abs/Desktop/data'
  data_dir_list = os.listdir(data_path)
  
  for dataset in data_dir_list:
      img_list=os.listdir(data_path+'/'+dataset)
      print ('Loaded the images of dataset-'+'{}\n'.format(dataset))
  </code></pre>