[OMCSessionCmd] ensure options are strings

Author: syntron

OMPython/OMCSession.py

@@ -112,7 +112,7 @@ def _ask(self, question: str, opt: Optional[list[str]] = None, parsed: Optional[
         if opt is None:
             expression = question
         elif isinstance(opt, list):
-            expression = f"{question}({','.join(opt)})"
+            expression = f"{question}({','.join([str(x) for x in opt])})"
         else:
             raise Exception(f"Invalid definition of options for {repr(question)}: {repr(opt)}")