code: def applyIndex(self, lst, right):
      
      if len(right) != 1:
        raise exceptions.EvaluationError('%r can only be applied to one argument, got %r' % (self.left, self.right))
      right = right[0]
  
      if isinstance(right, int):
        return lst[right]
  
      raise exceptions.EvaluationError("Can't apply %r to argument (%r): integer expected, got %r" % (self.left, self.right, right))
docs: Apply a list to something else.