'Returns a valid grubby parameter for commands such as --update-kernel'

def _get_entry_selection(self, data):

    if self._is_number(data):
        return data
    elif (isinstance(data, str) and data.startswith('/')):
        return data
    elif isinstance(data, str):
        return self._kernel_for_title(data)
    else:
        raise ValueError("Bad    value    for    'kernel'    parameter.    Expecting    either    and    int    (index)    or    string    (kernel    or    title)")
