title: i keep getting "Invalid result type, int expected, <class 'NoneType'> found"
body: <pre class="lang-py prettyprint-override"><code>def solution(A):
      # write your code in Python 3.6
      count=0
      for i in range(len(A)):
          for j in range(len(A)):
              if j!=i:
                  if A[i]==A[j]:
                      count = count+1
                  else:
                      count = count+0
  
          if count==0:
              return A[i]
  pass
  </code></pre>