Fix typo in a comment of abstract.c
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 24948db..034209c 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2463,7 +2463,7 @@
assert(kwnames == NULL || PyTuple_CheckExact(kwnames));
assert((nargs == 0 && nkwargs == 0) || stack != NULL);
/* kwnames must only contains str strings, no subclass, and all keys must
- be unique: these are implemented in Python/ceval.c and
+ be unique: these checks are implemented in Python/ceval.c and
_PyArg_ParseStack(). */
if (PyFunction_Check(callable)) {