title: How to check if there is a repeated value in a list and get that value
body: <p>How can I find the repeated value in a list? 
  There will always be only one repeated value</p>
  
  <p>for example:</p>
  
  <pre><code>numbers=[1,2,3,4,5,3]
  </code></pre>
  
  <p>I need to get the value 3</p>
  
  <p>This is what I was trying but it is sometimes printing the value of the same list 2 times.</p>
  
  <pre><code>endLoop=False
      for n1 in range(0,len(numbers)):
          for n2 in range(1,len(numbers)):
              if numbers[n1]==numbers[n2]:
                  print numbers
                  print numbers[n1]
                  endLoop=True
          if endLoop:
              break
  </code></pre>