Code at line 1297 in base.py can not work properly

[Tamabala]

Hi,

For the class HDDMbase in base.py, because the variable "include" was initially set as "()", the code "assert include is not None" at line 1297 can not prevent the user from leaving the include argument unassigned. (Instead, something like "len(include) != 0" can work)

Because of that, the error presented below will be reported because "include" is always empty.

If I get it wrong and it is something else that causes the error above, please let me know, I would really appreciate it.

Best
Wang