import frappe from frappe import _ class StudentNotInGroupError(frappe.ValidationError): pass def validate_student_belongs_to_group(student, student_group): groups = frappe.db.get_all("Student Group Student", ["parent"], dict(student=student, active=1)) if not student_group in [d.parent for d in groups]: frappe.throw( _("Student {0} does not belong to group {1}").format( frappe.bold(student), frappe.bold(student_group) ), StudentNotInGroupError, )