title: check if dataframe is of boolean type pandas
body: <p>I have a pandas DataFrame as below:</p>
  
  <pre><code>In [108]: df1
  Out[108]: 
                           v
  t                         
  2014-02-21 10:30:43  False
  2014-02-21 10:31:34  False
  2014-02-21 10:32:25  False
  2014-02-21 10:33:17  False
  2014-02-21 10:34:09  False
  2014-02-21 10:35:00  False
  2014-02-21 10:35:51  False
  </code></pre>
  
  <p>I need to check if the <code>dtype</code> of this dataframe is <code>bool</code>. I tried with:</p>
  
  <pre><code>In [109]: print isinstance(df1, bool)
  False
  </code></pre>
  
  <p>**It should return **True****</p>
  
  <p>How can I do this?</p>
  
  <p>Reference: <a href="https://stackoverflow.com/questions/14808945/check-if-variable-is-dataframe">check if variable is dataframe</a></p>