def load(self, filename, create_if_missing=True):
        filename = Path(filename)
        if not filename.exists() and create_if_missing:
            self.load_pip_requirements()
            with filename.open("w") as f:
                f.write(yaml.dump(self.serialized, default_flow_style=False,
                                  encoding=None))
            self.filename = filename
            return self.save(filename)
        with filename.open() as f:
            for group, requirements in yaml.load(f.read()).items():
                for requirement in requirements:
                    self[group].add(Requirement.coerce(requirement))
        self.filename = filename
def test_impl():
            df1 = pq.read_table('example.parquet').to_pandas()
            df2 = pq.read_table('example.parquet').to_pandas()
            A3 = pd.concat([df1.two, df2.two])
            return (A3 == 'foo').sum()