diff --git a/source/blender/python/intern/bpy_interface.c b/source/blender/python/intern/bpy_interface.c
index 66abc017fe1..9b685d5ba6e 100644
--- a/source/blender/python/intern/bpy_interface.c
+++ b/source/blender/python/intern/bpy_interface.c
@@ -625,13 +625,10 @@ bool BPY_execute_string_as_number(bContext *C, const char *expr, const bool verb
  */
 bool BPY_execute_string_as_string(bContext *C, const char *expr, const bool verbose, char **r_value)
 {
+	BLI_assert(r_value && expr);
 	PyGILState_STATE gilstate;
 	bool ok = true;
 
-	if (!r_value || !expr) {
-		return -1;
-	}
-
 	if (expr[0] == '\0') {
 		*r_value = NULL;
 		return ok;
@@ -662,13 +659,10 @@ bool BPY_execute_string_as_string(bContext *C, const char *expr, const bool verb
  */
 bool BPY_execute_string_as_intptr(bContext *C, const char *expr, const bool verbose, intptr_t *r_value)
 {
+	BLI_assert(r_value && expr);
 	PyGILState_STATE gilstate;
 	bool ok = true;
 
-	if (!r_value || !expr) {
-		return -1;
-	}
-
 	if (expr[0] == '\0') {
 		*r_value = 0;
 		return ok;
@@ -694,14 +688,13 @@ bool BPY_execute_string_as_intptr(bContext *C, const char *expr, const bool verb
 
 bool BPY_execute_string_ex(bContext *C, const char *expr, bool use_eval)
 {
+	BLI_assert(expr);
 	PyGILState_STATE gilstate;
 	PyObject *main_mod = NULL;
 	PyObject *py_dict, *retval;
 	bool ok = true;
 	Main *bmain_back; /* XXX, quick fix for release (Copy Settings crash), needs further investigation */
 
-	if (!expr) return -1;
-
 	if (expr[0] == '\0') {
 		return ok;
 	}