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 setUp(self):
        entry_Li = ComputedEntry("Li", -1.90753119)

        with open(os.path.join(PymatgenTest.TEST_FILES_DIR, "LiTiO2_batt.json")) as f:
            entries_LTO = json.load(f, cls=MontyDecoder)
            self.ie_LTO = InsertionElectrode.from_entries(entries_LTO, entry_Li)

        with open(os.path.join(PymatgenTest.TEST_FILES_DIR, "FeF3_batt.json")) as fid:
            entries = json.load(fid, cls=MontyDecoder)
            self.ce_FF = ConversionElectrode.from_composition_and_entries(Composition("FeF3"), entries)