Add parens for py3.8

Author: sterliakov

test-data/unit/check-inference.test

@@ -4013,7 +4013,7 @@ def check_or_nested(maybe: bool) -> None:
 def check_and(maybe: bool) -> None:
     foo = None
     bar = None
-    if maybe and (foo := [1])[bar := 0]:
+    if maybe and (foo := [1])[(bar := 0)]:
         reveal_type(foo)  # N: Revealed type is "builtins.list[builtins.int]"
         reveal_type(bar)  # N: Revealed type is "builtins.int"
     else:
@@ -4036,7 +4036,7 @@ def check_and_nested(maybe: bool) -> None:
 def check_or(maybe: bool) -> None:
     foo = None
     bar = None
-    if maybe or (foo := [1])[bar := 0]:
+    if maybe or (foo := [1])[(bar := 0)]:
         reveal_type(foo)  # N: Revealed type is "Union[builtins.list[builtins.int], None]"
         reveal_type(bar)  # N: Revealed type is "Union[builtins.int, None]"
     else: