title: Check Dataframe for certain string and return the column headers of the columns that string is found in
body: <p>I have a dataframe that looks something like this:
  <a href="https://i.stack.imgur.com/fKg9X.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/fKg9X.png" alt="enter image description here"></a>  </p>
  
  <p>Now I simply want to return the headers of the columns that have the string "worked" to a list. </p>
  
  <p>So that in this case the list only includes lst=["OBE"]</p>