def load(self, requirements_file=None):
        """Load or reload requirements from a requirements.txt file.

        :param requirements_file: if not given, the filename used from
            initialization will be read again.
        """
        if requirements_file is None:
            requirements_file = self.filename
            if requirements_file is None:
                raise ValueError("no filename provided")
        elif isinstance(requirements_file, text_type):
            requirements_file = Path(requirements_file)
        self.clear()
        with requirements_file.open() as f:
            self.loads(f.read())

        if isinstance(requirements_file, (text_type, Path)):
            self.filename = requirements_file
def test_structures_with_wchar(self):
        try:
            c_wchar
        except NameError:
            return # no unicode

        class PersonW(Structure):
            _fields_ = [("name", c_wchar * 12),
                        ("age", c_int)]

        p = PersonW("Someone \xe9")
        self.assertEqual(p.name, "Someone \xe9")

        self.assertEqual(PersonW("1234567890").name, "1234567890")
        self.assertEqual(PersonW("12345678901").name, "12345678901")
        # exact fit
        self.assertEqual(PersonW("123456789012").name, "123456789012")
        #too long
        self.assertRaises(ValueError, PersonW, "1234567890123")