GetUpdate.
        [Preview API] Returns a single update for a work item
        :param int id:
        :param int update_number:
        :param str project: Project ID or project name
        :rtype: :class:`<WorkItemUpdate> <azure.devops.v5_1.work-item-tracking.models.WorkItemUpdate>`

def get_update(self, id, update_number, project=None):
        """GetUpdate.
        [Preview API] Returns a single update for a work item
        :param int id:
        :param int update_number:
        :param str project: Project ID or project name
        :rtype: :class:`<WorkItemUpdate> <azure.devops.v5_1.work-item-tracking.models.WorkItemUpdate>`
        """
        route_values = {}
        if project is not None:
            route_values['project'] = self._serialize.url('project', project, 'str')
        if id is not None:
            route_values['id'] = self._serialize.url('id', id, 'int')
        if update_number is not None:
            route_values['updateNumber'] = self._serialize.url('update_number', update_number, 'int')
        response = self._send(http_method='GET',
                              location_id='6570bf97-d02c-4a91-8d93-3abe9895b1a9',
                              version='5.1-preview.3',
                              route_values=route_values)
        return self._deserialize('WorkItemUpdate', response)