1 files changed, 6 insertions, 1 deletions
diff --git a/py/objfilter.c b/py/objfilter.c
index 6696ffe32..18225ac10 100644
--- a/py/objfilter.c
+++ b/py/objfilter.c
@@ -1,8 +1,10 @@
 #include <stdlib.h>
 #include <assert.h>
 
+#include "nlr.h"
 #include "misc.h"
 #include "mpconfig.h"
+#include "mpqstr.h"
 #include "obj.h"
 #include "runtime.h"
 
@@ -14,8 +16,11 @@ typedef struct _mp_obj_filter_t {
 
 static mp_obj_t filter_make_new(mp_obj_t type_in, int n_args, const mp_obj_t *args) {
     /* NOTE: args are backwards */
-    mp_obj_filter_t *o = m_new_obj(mp_obj_filter_t);
+    if (n_args != 2) {
+        nlr_jump(mp_obj_new_exception_msg(MP_QSTR_TypeError, "filter expected 2 arguments"));
+    }
     assert(n_args == 2);
+    mp_obj_filter_t *o = m_new_obj(mp_obj_filter_t);
     o->base.type = &filter_type;
     o->fun = args[1];
     o->iter = rt_getiter(args[0]);