Note that this is contrary to the convention used in the Erlang community, where the number is used to disambiguate function definitions with different parameter counts, e.g. in https://www.erlang.org/docs/18/man/supervisor.html we see definitions of `start_link/2` and `start_link/3`.

It is a stylistic convention to always add this number to any reference to a function, even if there is only one definition.