In the Protocols lecture, we mainly wrote a medium$-$sized program that implemented a Polling client $($i$.$e$.,$ a program that can interact with the Polling server, so that a user can see the questions, vote on them, and see the results without knowing the details of how the Polling protocol works$).$

In polling.py$,$ three of the functions $\_$read$\_$line, $\_$expect$\_$line, and $\_$write$\_$line $$ were marked as protected, while the others were not. In a sentence or two, what would be a good rationale for making these protected? In other words, why would I have written them that way, instead of making them public instead? $($Note that I$\text{'}$m asking specifically about these functions, not for a general definition of what public or protected functions are. This isn't about the concept; it's about the application of the concept.$)$