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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def not_evaluator(conditions, leaf_evaluator):
 """ Evaluates a list of conditions as if the evaluator had been applied to a single entry and NOT was applied to the result. Args: conditions: List of conditions ex: [operand_1, operand_2]. leaf_evaluator: Function which will be called to evaluate leaf condition values. Returns: Boolean: - True if the operand evaluates to False. - False if the operand evaluates to True. None: if conditions is empty or condition couldn't be evaluated. """

  if not len(conditions) > 0:
    return None

  result = evaluate(conditions[0], leaf_evaluator)
  return None if result is None else not result