Given a set of options related to shell startup, return the actual
        options that will be applied.
        @returns 4-tuple representing applied value of each option.

def startup_capabilities(cls, rcfile=False, norc=False, stdin=False,
                             command=False):
        """
        Given a set of options related to shell startup, return the actual
        options that will be applied.
        @returns 4-tuple representing applied value of each option.
        """
        raise NotImplementedError