title: How to check if a Pandas row contains an empty set
body: <p>I want to check if a Pandas Dataframe row contains an empty set in a specific column, i.e. </p>
  
  <pre><code>d = {'col1': [1, 2], 'col2': [3, {}]}
  df2 = pd.DataFrame(data=d)
  
  
      col1    col2
  0   1       3
  1   2       {}
  </code></pre>
  
  <p>and then</p>
  
  <pre><code>df2['col_2_contains_empty_set'] = ? #  how to implement this
  </code></pre>
  
  <p>should give</p>
  
  <pre><code>    col1    col2    col_2_contains_empty_set
  0   1       3       False
  1   2       {}      True
  </code></pre>
  
  <p>What's the correct way to do this? Can't do </p>
  
  <pre><code>bool(df['col2']) 
  </code></pre>
  
  <p>or</p>
  
  <pre><code>df['col2'].bool()
  </code></pre>
  
  <p>as <code>Series</code> are have ambiguous Boolean values, I think. </p>