diff --git a/src/if_py_both.h b/src/if_py_both.h
index 1801967..3380142 100644
--- a/src/if_py_both.h
+++ b/src/if_py_both.h
@@ -1996,6 +1996,7 @@
 		PyObject	*todecref;
 		char_u		*key;
 		dictitem_T	*di;
+		hashitem_T	*hi;
 
 		if (!(fast = PySequence_Fast(item, "")))
 		{
@@ -2052,7 +2053,8 @@
 
 		Py_DECREF(fast);
 
-		if (dict_add(dict, di) == FAIL)
+		hi = hash_find(&dict->dv_hashtab, di->di_key);
+		if (!HASHITEM_EMPTY(hi) || dict_add(dict, di) == FAIL)
 		{
 		    RAISE_KEY_ADD_FAIL(di->di_key);
 		    Py_DECREF(iterator);
diff --git a/src/version.c b/src/version.c
index b2a3ce4..c74f062 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1283,
+/**/
     1282,
 /**/
     1281,