def __init__(self, package, version):
        """Construct a new requirement.

        :param package: the package name.
        :param version: a semver compatible version specification.
        """
        self.package = package
        self.version = version
        if self.version and not re.match(r"[<=>~]", version[:2]):
            self.version = "=={}".format(self.version)
def test_impl():
            df1 = pq.read_table('example.parquet').to_pandas()
            df2 = pq.read_table('example.parquet').to_pandas()
            A3 = pd.concat([df1, df2])
            return (A3.two == 'foo').sum()