title: differences between "d = dict()" and "d = {}"
body: <pre><code>$ python2.7 -m timeit 'd={}'
  10000000 loops, best of 3: 0.0331 usec per loop
  $ python2.7 -m timeit 'd=dict()'
  1000000 loops, best of 3: 0.19 usec per loop
  </code></pre>
  
  <p>Why use one over the other?</p>