title: Python ImportError: cannot import name '__version__'
body: <p>Below code is part of my code</p>
  
  <pre><code>import time
  import matplotlib
  import matplotlib.pylab as plt
  plt.rcParams["axes.grid"] = False
  
  import mmcv
  from mmcv.runner import load_checkpoint
  import mmcv.visualization.image as mmcv_image
  
  
  def imshow(img, win_name='', wait_time=0): plt.figure(
      figsize=(50, 50)); plt.imshow(img)
  
  
  mmcv_image.imshow = imshow
  from mmdet.models import build_detector
  from mmdet.apis import inference_detector, show_result, init_detector
  </code></pre>
  
  <p>and this part has an error</p>
  
  <pre><code>from mmcv.runner import load_checkpoint
  </code></pre>
  
  <p>error is like below</p>
  
  <pre><code>from PIL import Image, ImageOps, ImageEnhance, __version__ as PILLOW_VERSION
  ImportError: cannot import name '__version__'
  </code></pre>
  
  <p>but I have already executed pip install Pillow, please is anyone could help me...</p>