title: Drop duplicate Pandas dataframes from a list based on a subset of columns
body: <p>I have a list of dataframes named <code>tempDFList</code>.</p>
  <pre><code>type(tempDFList)
  list
  
  type(tempDFList[0])
  pandas.core.frame.DataFrame
  </code></pre>
  <p>They have a subset of columns in common including <code>Previous Pivot Price</code> &amp; <code>Pivot Price</code> but not all columns are the same.</p>
  <p>How do I use something like <code>drop_duplicates</code> using default <code>keep='first</code> to ensure I don't have any frames with the same <code>Previous Pivot Price</code> &amp; <code>Pivot Price</code> in the <code>tempDFList</code>?</p>
  <p>Desired output is a list of dataframes that doesn't have any frames with the same <code>Previous Pivot Price</code> &amp; <code>Pivot Price</code>.  For the sample data below only two would remain.</p>
  <p><strong>Code from <code>df.to_dict</code></strong></p>
  <p>Each is a separate dataframe with one row.  These are in <code>tempDFList</code>.</p>
  <pre><code>{'Re_236_H1': {0: nan},
   'Re_382_H1': {0: nan},
   'Re_50_H1': {0: 0.8677},
   'Re_618_H1': {0: 0.8668},
   'Previous Pivot Date': {0: '2021-04-13 09:00:00'},
   'Previous Pivot Price': {0: 0.86408},
   'Date': {0: Timestamp('2021-04-13 13:00:00')},
   'Pivot Price': {0: 0.871180},
   'Pivot Length': {0: 0.007099}}
  
  
  {'Re_236_M15': {0: nan},
   'Re_382_M15': {0: nan},
   'Re_50_M15': {0: 0.8677},
   'Re_618_M15': {0: 0.8668},
   'Previous Pivot Date': {0: '2021-04-13 09:45:00'},
   'Previous Pivot Price': {0: 0.86408},
   'Date': {0: Timestamp('2021-04-13 13:00:00')},
   'Pivot Price': {0: 0.871180},
   'Pivot Length': {0: 0.007099}}
  
  {'Re_236_H4': {0: nan},
   'Re_382_H4': {0: nan},
   'Re_50_H4': {0: 0.8677},
   'Re_618_H4': {0: 0.8668},
   'Previous Pivot Date': {0: '2021-04-14 09:00:00'},
   'Previous Pivot Price': {0: 0.89408},
   'Date': {0: Timestamp('2021-04-13 13:00:00')},
   'Pivot Price': {0: 0.891180},
   'Pivot Length': {0: 0.008099}}
  </code></pre>