title: Return names which exist in second dataframe
body: <p>I am currently trying to populate a dropdown list with labels that need to exist in a second dataframe, currently, the below is returning a True and False option:</p>
  <pre><code>[{'label': i, 'value': i} for i in sorted(dff.Opp.isin(df2['Name']).unique().astype(str))],
  </code></pre>
  <p>any advice on what needs to be changed?</p>
  <p>EDIT: DataFrame examples:</p>
  <pre><code>df1:
  0  Opp
  1  Test2
  2  Test4
  3  Test6
  4  Test7
  
  df2:
  0  Name
  1  Test1
  2  Test2
  3  Test3
  4  Test4
  5  Test5
  </code></pre>
  <p>Expected outcome:
  dropdown would be populated with Test2 and Test4 as they are in both dataframes</p>