title: How to check if a list contains duplicate items?
body: <p>I want to validate a list to make sure that there are no duplicate items. My problem is that I don't know how to do this in the if statement. Is there a method or something in python that will return False if there are duplicates in the list?</p>
  
  <p>Here is what I had in mind:</p>
  
  <pre><code>lst = ["1","2","3","3","4"]
  
  if #lst contains no duplicates :
      print("success")
  else:
      print("duplicate found")
  </code></pre>
  
  <p>Thanks in advance.</p>