AttributeError:

Hello,

I am getting this error in my app:

Although, the method is defined and in the whitelist

    @frappe.whitelist()
    def get_items(self):
            mr_dtl=frappe.db.sql("""select parent,item,required_by_date,special_instruction,end_user,req_quantity,dlv_quantity
            from `tabMaterial Requisition Child` where docstatus=1 and req_quantity > dlv_quantity""")

            msgprint(_("inside get_items"))