'Set grubby path.
If path is not provided, check first if there\'s a built grubby,
then look for the system grubby.
:param path: Alternate grubby path.'

def _set_path(self, path=None):

    if (path is None):
        if os.path.exists(GRUBBY_DEFAULT_USER_PATH):
            self.path = GRUBBY_DEFAULT_USER_PATH
        else:
            self.path = GRUBBY_DEFAULT_SYSTEM_PATH
    else:
        self.path = path
