title: Argument must be a string, a bytes-like object or a number, not 'slice'
body: <p>I am having troubles with deleting slices from a numpy array.</p>
  <pre><code>x_train[:,:,0] 
  </code></pre>
  <p>returns the data I want to delete</p>
  <p>but</p>
  <pre><code>np.delete(x_train, np.s_[:,:,0])
  </code></pre>
  <p>throws the exception
  TypeError: int() argument must be a string, a bytes-like object or a number, not 'slice'</p>
  <p>But in the documentation it is written</p>
  <blockquote>
  <p>Return a new array with sub-arrays along an axis deleted. For a one dimensional array, this returns those entries not returned by arr[obj].</p>
  <p>obj : slice, int or array of ints</p>
  <p>Indicate which sub-arrays to remove.</p>
  </blockquote>