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diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 5a3b03f..ef15a39 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -1746,10 +1746,10 @@
typedef struct {
PyObject_HEAD
PyObject *pools; /* tuple of pool tuples */
- Py_ssize_t *maxvec;
- Py_ssize_t *indices;
- PyObject *result;
- int stopped;
+ Py_ssize_t *maxvec; /* size of each pool */
+ Py_ssize_t *indices; /* one index per pool */
+ PyObject *result; /* most recently returned result tuple */
+ int stopped; /* set to 1 when the product iterator is exhausted */
} productobject;
static PyTypeObject product_type;