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 _checkProvenance(self, resp, item, version, user, eventType,
                         matches=None, fileInfo=None, resource='item'):
        if resp is None:
            resp = self._getProvenance(item, user, resource=resource)
        self.assertStatusOk(resp)
        itemProvenance = resp.json
        self.assertEqual(itemProvenance['resourceId'], str(item['_id']))
        provenance = itemProvenance['provenance']
        self.assertEqual(provenance['eventType'], eventType)
        self.assertEqual(provenance['version'], version)
        self.assertEqual(str(provenance['eventUser']), str(user['_id']))
        if matches:
            for key in matches:
                self.assertEqual(provenance[key], matches[key])
        if fileInfo:
            for key in fileInfo:
                if isinstance(fileInfo[key], dict):
                    for subkey in fileInfo[key]:
                        self.assertEqual(provenance['file'][0][key][subkey],
                                         fileInfo[key][subkey])
                else:
                    self.assertEqual(provenance['file'][0][key], fileInfo[key])