title: format () : ValueError: Precision not allowed in integer format specifier
body: <p>I am a python newbie.I am just getting acquainted with format method.</p>
  
  <p>From a book that I am reading to learn python</p>
  
  <pre><code>What Python does in the format method is that it substitutes each argument
  value into the place of the specification. There can be more detailed specifications
  such as:
  decimal (.) precision of 3 for float '0.333'
  &gt;&gt;&gt; '{0:.3}'.format(1/3)
  fill with underscores (_) with the text centered
  (^) to 11 width '___hello___'
  &gt;&gt;&gt; '{0:_^11}'.format('hello')
  keyword-based 'Swaroop wrote A Byte of Python'
  &gt;&gt;&gt; '{name} wrote {book}'.format(name='Swaroop', book='A Byte of Python')
  </code></pre>
  
  <p>In the python interpreter if I try </p>
  
  <pre><code>print('{0:.3}'.format(1/3))
  </code></pre>
  
  <p>It gives the error </p>
  
  <pre><code> File "", line 24, in 
  ValueError: Precision not allowed in integer format specifier 
  </code></pre>