fix(report): Return if not list (#15849)

diff --git a/erpnext/education/report/student_monthly_attendance_sheet/student_monthly_attendance_sheet.py b/erpnext/education/report/student_monthly_attendance_sheet/student_monthly_attendance_sheet.py
index 0c7baa8..3f1d5b3 100644
--- a/erpnext/education/report/student_monthly_attendance_sheet/student_monthly_attendance_sheet.py
+++ b/erpnext/education/report/student_monthly_attendance_sheet/student_monthly_attendance_sheet.py
@@ -73,6 +73,7 @@
 	return att_map
 
 def get_students_with_leave_application(from_date, to_date, students_list):
+	if not students_list: return
 	leave_applications = frappe.db.sql("""
 		select student, from_date, to_date 
 		from `tabStudent Leave Application`