def transform(
        self,
        func: Callable[[_OutT], _NewOutT],
    ) -> _Pipeline[_InT, _NewOutT]:
        """Transform the output of the previous step.

        If used as the first step in a pipeline, the type of the field is used.
        That is, the transformation is applied to after the value is parsed to the field's type.
        """
        return _Pipeline[_InT, _NewOutT](self._steps + (_Transform(func),))
Transform the output of the previous step.

        If used as the first step in a pipeline, the type of the field is used.
        That is, the transformation is applied to after the value is parsed to the field's type.
        
pydantic/experimental/pipeline.py