My biggest struggle was with yield. With my Leader’s help I figured it out and was able to understand it’s usage.
I see it as more like a crossing guard for code. yield stops the method’s flow… inserts a method or value within the yielded method…. then picks-up up the orginal method’s flow.
Other ethen that I have not struggled with anything other then stinking syntax errors mainly because I have an end missing or in the wrong place.