'Check if TarFile is still open, and if the operation\'s mode
corresponds to TarFile\'s mode.'

def _check(self, mode=None):

    if self.closed:
        raise IOError(('%s    is    closed' % self.__class__.__name__))
    if ((mode is not None) and (self.mode not in mode)):
        raise IOError(('bad    operation    for    mode    %r' % self.mode))
    return
