...
File "C:\Users\Steven\LI\src\Interpreter.py", line 366, in difference
arg1, rest = retrieveParams(2, dict, *args)
File "C:\Users\Steven\LI\src\Interpreter.py", line 181, in retrieveParams
arg1, rest = string[0].execute(dict, string[1:], *args[1:])
MemoryError: stack overflow