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 GetLogs(region, stream_name, group_name, token=None):
  """Fetches the JSON formatted log stream starting at the token."""
  get_cmd = util.AWS_PREFIX + [
      '--region', region,
      'logs', 'get-log-events',
      '--start-from-head',
      '--log-group-name', group_name,
      '--log-stream-name', stream_name,
  ]
  if token:
    get_cmd.extend(['--next-token', token])
  stdout, _, _ = vm_util.IssueCommand(get_cmd)
  return json.loads(stdout)