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_initializers(self):
        class Person(Structure):
            _fields_ = [("name", c_char*6),
                        ("age", c_int)]

        self.assertRaises(TypeError, Person, 42)
        self.assertRaises(ValueError, Person, b"asldkjaslkdjaslkdj")
        self.assertRaises(TypeError, Person, "Name", "HI")

        # short enough
        self.assertEqual(Person(b"12345", 5).name, b"12345")
        # exact fit
        self.assertEqual(Person(b"123456", 5).name, b"123456")
        # too long
        self.assertRaises(ValueError, Person, b"1234567", 5)