def GetElapsedMs(start_time, end_time):
  """Return milliseconds elapsed between |start_time| and |end_time|.

  Args:
    start_time: seconds as a float (or string representation of float).
    end_time: seconds as a float (or string representation of float).
  Return:
    milliseconds elapsed as integer.
  """
  return int((float(end_time) - float(start_time)) * 1000)