对所有元素进行一对一映射变换，等同于 :func:`bigflow.transforms.map(self, fn, *side_inputs, **options) ` Args: fn (function): 变换函数 *side_inputs: 参与运算的SideInputs **options: 可配置选项 Returns: PCollection: 变换结果
(self, fn, *side_inputs, **options)
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no outgoing calls
no test coverage detected