Add a Pipeline to be applied before this processing pipeline.

        Arguments:
            pipeline: The Pipeline or callable to apply before this
                Pipeline.

def add_before(self, pipeline):
        """Add a Pipeline to be applied before this processing pipeline.

        Arguments:
            pipeline: The Pipeline or callable to apply before this
                Pipeline.
        """
        if not isinstance(pipeline, Pipeline):
            pipeline = Pipeline(pipeline)
        self.pipes = pipeline.pipes[:] + self.pipes[:]
        return self