Xposed: What happens to return value when using param.setResult(null)?

Question

If I have code: if(blockedMethod()) {code}

and I set a hook to blockedMethod such as:

            new XC_MethodHook() {
                @Override
                protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                    if(bootCompleted) {
                        param.setResult(null); //Blocks method call.
                    }
                }

                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    param.setResult(false); //Should I do this if I want a result?
                }
            }

What happens to return value when using param.setResult(null) in before-hook? Will {code} be executed or not? What is returned? Should I use param.setResult() to actually get a return value at all? Is the if-clause even executed?