title: File "Solution.py", line 41, in <module> fptr.write(result + '\n') TypeError: unsupported operand type(s) for +: 'NoneType' and 'str'
body: <pre class="lang-py prettyprint-override"><code>def getPhoneNumber(s):
      # Write your code here
      ref_dict = {
          'one' : '1',
          'two' : '2',
          'three' : '3',
          'four' : '4',
          'five' : '5',
          'six' : '6',
          'seven' : '7',
          'eight' : '8',
          'nine' : '9',
          'zero' : '0'
      }
      
      conversion = ''.join(ref_dict[ele] for ele in s.split())
      
  if __name__ == '__main__':
      fptr = open(os.environ['OUTPUT_PATH'], 'w')
  
      s = raw_input()
  
      result = getPhoneNumber(s)
  
      fptr.write(result + '\n')
  
      fptr.close()
  </code></pre>