docs: def RtlGetVersion(os_version_info_struct):
    """Wraps the lowlevel RtlGetVersion routine.
  
    Args:
      os_version_info_struct: instance of either a RTL_OSVERSIONINFOW structure
                              or a RTL_OSVERSIONINFOEXW structure,
                              ctypes.Structure-wrapped, with the
                              dwOSVersionInfoSize field preset to
                              ctypes.sizeof(self).
  
    Raises:
      OSError: if the underlaying routine fails.
  
    See: https://msdn.microsoft.com/en-us/library/
    windows/hardware/ff561910(v=vs.85).aspx .
    """
    rc = ctypes.windll.Ntdll.RtlGetVersion(ctypes.byref(os_version_info_struct))
    if rc != 0:
      raise OSError("Getting Windows version failed.")