Return the VCS-specific command arguments.

def to_args(self):
        # type: () -> List[str]
        """
        Return the VCS-specific command arguments.
        """
        args = []  # type: List[str]
        rev = self.arg_rev
        if rev is not None:
            args += self.vcs.get_base_rev_args(rev)
        args += self.extra_args

        return args