The proxy related environment variables are not required to by all uppercase in my experience. At least all the common cli tools (wget, git, curl) support proxy related variables in lowercase.
The systems I'm working with have proxy environment variables names in lowercase and it never caused any problems.
So the intended benefit of `get_env` is to read environment variables regardless if the are written uppercase or lowercase. Looking them up as is (`ENV[name]`) is not strictly necessary, I just wanted the method to be able to read variables in mixed case provided you pass in the exact string.