def test_add_already_added(self):
        prio_set_list = event._PrioritizedSetList()
        obj = object()
        prio_set_list.add(0, obj)

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.add(0, obj)
        excinfo.match(r"has already been added")

        with pytest.raises(ValueError) as excinfo:
            prio_set_list.add(1, obj)
        excinfo.match(r"has already been added")
def post(txt, contact, parenttype=None, notify=False, subject=None):
	"""post message"""

	d = frappe.new_doc('Communication')
	d.communication_type = 'Notification' if parenttype else 'Chat'
	d.subject = subject
	d.content = txt
	d.reference_doctype = 'User'
	d.reference_name = contact
	d.sender = frappe.session.user
	d.insert(ignore_permissions=True)

	delete_notification_count_for("Messages")

	if notify and cint(notify):
		if contact==frappe.session.user:
			_notify([user.name for user in get_enabled_system_users()], txt)
		else:
			_notify(contact, txt, subject)

	return d