In some plugins you may even end with having no non-anonymous function
2. If function cannot be anonymous (because it is is to be used by `sort()`, for
example), then its name should be added to `s:_functions` list.
3. If you define a command, its name should go to `s:_commands` list, same for
autocommand groups (`s:_augroups`).
4. All script-local variables whose name starts with `s:_` are reserved and
should be used only in a way described in documentation.