title: Alert and stop script if duplicate filename found
body: <p>I am  trying to find any duplicate filename found in several sub-folders and stop the script and prompt the user about the duplicate. </p>
  
  <p>Using this example filenames:</p>
  
  <pre><code>Money_03012019_2019.csv
  Money_04012019_2019.csv
  Money_04012019_2019 - Copy.csv
  Money_05012019_2019.csv
  Money_06012019_2019.csv
  </code></pre>
  
  <p>The duplicate filename can be in any sub-folders (the - copy was just trying to mimic the filename but the code should be able to know that it is a duplicate based on the DDMMYYYY in the filename).</p>
  
  <p>I have tried the following code:</p>
  
  <pre><code>flist = glob.glob('/**/Money_*_*.csv', recursive=True)    
  
  if len(set(flist)) == len(flist):
      print('No Duplicate')
  else:
      print('Duplicate Found')
  </code></pre>
  
  <p>But it just doesn't work even after I play around. I thought the set() and len method is the way to go for this (set will avoid duplicate by checking if it is equal to the length of the flist)?</p>
  
  <p>Thanks.</p>