missing pieces

Author: Frederic Peschanski

mrpython/StudentRunner.py

@@ -41,6 +41,7 @@ def install_locals(locals):
     locals['Iterable'] = typing.Iterable
     locals['Tuple'] = typing.Tuple
     locals['Dict'] = typing.Dict
+    locals['Optional'] = typing.Optional
 
     # hack
     locals['Image'] = None

mrpython/typechecking/typechecker.py

@@ -1167,7 +1167,7 @@ def type_infer_EMult(expr, ctx):
 
     # first case if the left operand is a string
 
-    if isinstance(left_type, StrType):
+    if isinstance(left_type, (StrType, ListType, SequenceType)):
         right_type = type_expect(ctx, expr.right, IntType())
         if not right_type:
             return None