Changing Environment Paths using D language's Phobos Library

[BoQsc via Digitalmars-d-learn]

I would like to remove/add/change Environment Paths using D 
language's Phobos.
https://en.wikipedia.org/wiki/PATH_(variable)
I saw in the documentation that there is a class file 
"std.process : environment" that has the supposed ability to 
minipulate environment variables.
https://dlang.org/library/std/process/environment.html

I couldn't find a good documentation on how to search and replace 
strings using Phobos Library. However it seems that it might be 
possbile by importing "std.array : replace" function.
https://forum.dlang.org/post/jnua50$1e4a$1...@digitalmars.com
https://dlang.org/library/std/array/replace.html

So, here we are, testing if it is possible to retrieve and set 
the Environmental Variables.

import std.stdio   : writeln;
import std.array   : replace;
import std.process : environment;

void main(){


	// Retrieve environment variable "path" for testing if it is 
possible
        // to retrieve it by using D language Phobos Library
        auto environmentPaths = environment.get("path");
	writeln(environmentPaths); // Works as expected: we can see the 
output of Paths.
        
	// Create a new Environement variable for testing if it is 
possible
        // to Create it with D language Phobos Library
	environment.opIndexAssign("variableName", "Some Random Value 
Here");
        auto environmentalVariable = environment.get("variableName");
	writeln(environmentalVariable); //Unexpected: absolutely no 
output.
        
        
        

Alright, now that we see it is possible to retrieve environmental 
variable, that's great.

However, setting the variable via "environment.opIndexAssign" 
seems to not work.
What should we do?
I don't know.