title: Python, PEP-8 and multi-line dict formatting
body: <p>I have to declare some <code>dict</code> in Python. I write such a code: </p>
  
  <pre><code>class MegaClass(object):
      _activation_grad_classes = \
      {
          activation.ForwardStrictRELU: activation.BackwardStrictRELU,
          activation.ForwardLog: activation.BackwardLog,
          activation.ForwardSinCos: activation.BackwardSinCos
      }
  </code></pre>
  
  <p>And get a PEP-8 error: <code>E122 continuation line missing indentation or outdented</code>.</p>
  
  <p>How can I fix it?</p>