title: Deformable convolution in tensorflow
body: <p>I tried to use the <code>tensorlayer</code> in python 3.5 to run a simple code. I have this error::</p>
  
  <pre><code>[TL] DeformableConv2d ab: n_filter: 32, filter_size: (3, 3) act:relu
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
    File "/home/anaconda3/lib/python3.5/site-packages/tensorlayer/deprecation.py", line 24, in wrapper
      return f(*args, **kwargs)
    File "/home/anaconda3/lib/python3.5/site-packages/tensorlayer/layers/convolution.py", line 971, in __init__
      tf.reshape()
  TypeError: reshape() missing 2 required positional arguments: 'tensor' and 'shape'
  </code></pre>
  
  <p>The code is:</p>
  
  <pre><code>import tensorflow as tf
  import tensorlayer as tl
  
  inp = tf.zeros([1,50,50,3])
  inp = tl.layers.InputLayer(inp, 'inp')
  
  offset = tl.layers.Conv2d(inp, 18, (3,3), (1,1), padding="SAME")
  
  d = tl.layers.DeformableConv2d(inp, offset, 32, (3,3), name='a')
  </code></pre>
  
  <p>Why is this happening?</p>