How to install Ubuntu using internet from proxy defined by a PAC file

The only way to install and updatde my fresh desktop Ubuntu 18 LTS (installed by pendrive without internet) is using a proxy with a PAC file:

myip = myIpAddress();  function FindProxyForURL(url, host) {         if (isPlainHostName(host))         return "DIRECT";           // Bypass Local Network      if (isInNet(dnsResolve(host), "10.0.0.0", "255.0.0.0")         || isInNet(dnsResolve(host), "etc", "etc")         || ...          || isInNet(dnsResolve(host), "etc", "etc"))          return "DIRECT";           // Bypass Local IP      if ( isInNet(dnsResolve(host), "etc", "etc")          || isInNet(dnsResolve(host), "etc", "etc")          || isInNet(dnsResolve(host), "etc", "etc"))          return "DIRECT";           // Bypass URL      if ((host == "domain1")            || (host == "domain2")         || (host == "etc")          || (host == "etc"))          return "DIRECT";           // Bypass Domain      if (shExpMatch(url, "*.domain")       || shExpMatch(url, "*.etc")       || shExpMatch(url, "*.etc"))          return "DIRECT";           //Encaminha todo o trafego que restante para o PROXY CORPORATIVO          return "PROXY _IP_:8080; DIRECT"; } 

How to install and use UBUNTU with PAC proxy?

When using install wizard there are no option to upload PAC file.