def get(self, id, pk='id', deleted=False):
        try:
            if pk == 'id':
                id = int(id)
            if deleted:
                spec = {pk: id}
            else:
                spec = {pk: id, 'data': {'$exists': 1}}
            fields = {'_id': 0}
            row = self.db.docs.find_one(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return Document(**row)
        raise NotFoundError('%s %s not found' % (pk, id))
def get_list(arg=None):
	"""get list of messages"""
	frappe.form_dict['limit_start'] = int(frappe.form_dict['limit_start'])
	frappe.form_dict['limit_page_length'] = int(frappe.form_dict['limit_page_length'])
	frappe.form_dict['user'] = frappe.session['user']

	# set all messages as read
	frappe.db.begin()
	frappe.db.sql("""UPDATE `tabCommunication` set seen = 1
		where
			communication_type in ('Chat', 'Notification')
			and reference_doctype = 'User'
			and reference_name = %s""", frappe.session.user)

	delete_notification_count_for("Messages")

	frappe.local.flags.commit = True

	if frappe.form_dict['contact'] == frappe.session['user']:
		# return messages
		return frappe.db.sql("""select * from `tabCommunication`
			where
				communication_type in ('Chat', 'Notification')
				and reference_doctype ='User'
				and (owner=%(contact)s
					or reference_name=%(user)s
					or owner=reference_name)
			order by creation desc
			limit %(limit_start)s, %(limit_page_length)s""", frappe.local.form_dict, as_dict=1)
	else:
		return frappe.db.sql("""select * from `tabCommunication`
			where
				communication_type in ('Chat', 'Notification')
				and reference_doctype ='User'
				and ((owner=%(contact)s and reference_name=%(user)s)
					or (owner=%(contact)s and reference_name=%(contact)s))
			order by creation desc
			limit %(limit_start)s, %(limit_page_length)s""", frappe.local.form_dict, as_dict=1)