title: Python self takes args, self(args)
body: <p>I'm not quite understand what this code mean:</p>
  
  <pre><code># instantiate the input layer
  x = Input(batch_shape=batch_input_shape,
            dtype=input_dtype, name=name)
  # this will build the current layer
  # and create the node connecting the current layer
  # to the input layer we just created.
  self(x)
  </code></pre>
  
  <p>This code is inside a member function of a class, please refer to <a href="https://github.com/fchollet/keras/blob/master/keras/engine/topology.py" rel="nofollow">https://github.com/fchollet/keras/blob/master/keras/engine/topology.py</a> line 341.
  When I step into the self(x), it jumps to another member function __call__ of this class. Why does this happen? Thanks.</p>