运行“ a2enmod php7.0”时，出现以下错误。这只是可忽略的还是问题？我该如何解决？
Considering dependency mpm_prefork for php7.0:
Considering conflict mpm_event for mpm_prefork:
Considering conflict mpm_worker for mpm_prefork:
Module mpm_prefork already enabled
Considering conflict php5 for php7.0:
Module php7.0 already enabled