def __call__(self, stream):

        # Run the stream over all the filters on the pipeline
        for filter in self:
            # Functions and callable objects (objects with '__call__' method)
            if callable(filter):
                stream = filter(stream)

            # Normal filters (objects with 'process' method)
            else:
                stream = filter.process(None, stream)

        # If last filter return a generator, staticalize it inside a list
        if isinstance(stream, GeneratorType):
            return list(stream)
        return stream
Run the pipeline
dataset/ETHPy150Open andialbrecht/sqlparse/sqlparse/pipeline.py/Pipeline.__call__