fetch query for assessment group (#9120)

diff --git a/erpnext/schools/doctype/assessment_plan/assessment_plan.js b/erpnext/schools/doctype/assessment_plan/assessment_plan.js
index 3c9ab80..abdb0c8 100644
--- a/erpnext/schools/doctype/assessment_plan/assessment_plan.js
+++ b/erpnext/schools/doctype/assessment_plan/assessment_plan.js
@@ -6,7 +6,17 @@
 cur_frm.add_fetch("supervisor", "instructor_name", "supervisor_name");
 
 frappe.ui.form.on("Assessment Plan", {
-        refresh: function(frm) {
+    onload: function(frm) {
+        frm.set_query("assessment_group", function(doc, cdt, cdn) {
+            return{
+                filters: {
+                    'is_group': 0
+                }
+            }
+        });
+    },
+
+    refresh: function(frm) {
         if (frm.doc.docstatus == 1) {
             frm.add_custom_button(__("Assessment Result"), function() {
                 frappe.route_options = {
diff --git a/erpnext/schools/doctype/assessment_plan/assessment_plan.py b/erpnext/schools/doctype/assessment_plan/assessment_plan.py
index 7f83c01..f988886 100644
--- a/erpnext/schools/doctype/assessment_plan/assessment_plan.py
+++ b/erpnext/schools/doctype/assessment_plan/assessment_plan.py
@@ -36,4 +36,4 @@
 		for d in self.assessment_criteria:
 			max_score += d.maximum_score
 		if self.maximum_assessment_score != max_score:
-			frappe.throw(_("Sum of Scores of Assessment Criteria needs to be {0}.".format(self.maximum_assessment_score)))
\ No newline at end of file
+			frappe.throw(_("Sum of Scores of Assessment Criteria needs to be {0}.".format(self.maximum_assessment_score)))