title: Python find the common element in lists
body: <p>I need to find the common element from 2 lists, and if there is none, print []. I managed to do the first part, but when I add else it goes sideways...</p>
  
  <pre><code>def find_common(L1,L2):
     for element in L1:
          if element in L2:
              return (element)
          else :   
              return []
  
  
  
  L1 = ['Dancing', 'Computers', 'Rowing']
  L2 = ['Computers', 'Books', 'Movies']
  
  print(find_common(L1,L2)) #should print "Computers"
  
  L1 = ['Fishing'] 
  L2 = ['Swimming']
  
  print(find_common(L1,L2)) #should print []
  </code></pre>
  
  <p>The output is for this code is [][] right now. If I don't add the else function, the output is "Computer", which is correct. The problem is that I need to check also some lists that don't have a common element and output [], and here it goes wrong. What is my mistake? Thank you. </p>