It was my first idea — to add a parameter to full_messages, but without an alias.
It would be great, if we could avoid the code duplication this way, but implementations are different enough to write them independently.
This way things become more comlicated. Along with introducing a new method, we change the existing one; and also there would be two ways of solving the particular task, between which programers should choose. I don't even say, that in this case full_massages will work slower :-).