title: temporarily change pandas’ set_option for displaying dataframe
body: <p>I'm using Jupyter notebook and imported many <code>DataFrames</code> and one of them contains very long strings. Thus, I'd like to temporarily change <code>pandas</code>' display option without affect the global setting. I tried to use <code>with</code>: </p>
  
  <pre><code>with pd.set_option('display.max_colwidth', 220): 
      df.head()
  </code></pre>
  
  <p>But it doesn't work and returns <code>AttributeError: __enter__.</code></p>
  
  <p>Am I missing something? </p>