comefrom: <garvit244>24_1.py
code: def swapPairs( head):
      if head is None:
          return head
      
      ref = head
      
      while ref is not None and ref.next is not None:
          ref.val, ref.next.val = ref.next.val, ref.val
          ref = ref.next.next
          
      return head
masked: def sample_funcname ( var_0 ) :
      if var_0 is None :
          return var_0
      var_2 = var_0
      while var_2 is not None and var_2.next is not None :
          var_2.val , var_2.next.val = var_2.next.val , var_2.val
          var_2 = var_2.next.next
      return var_0
  