User www-data may run the following commands on walla:
(ALL) NOPASSWD: /sbin/ifup
(ALL) NOPASSWD: /usr/bin/python /home/walter/wifi_reset.py
(ALL) NOPASSWD: /bin/systemctl start hostapd.service
(ALL) NOPASSWD: /bin/systemctl stop hostapd.service
(ALL) NOPASSWD: /bin/systemctl start dnsmasq.service
(ALL) NOPASSWD: /bin/systemctl stop dnsmasq.service