def respond_activity_task_canceled(taskToken=None, details=None):
    """
    Used by workers to tell the service that the  ActivityTask identified by the taskToken was successfully canceled. Additional details can be optionally provided using the details argument.
    These details (if provided) appear in the ActivityTaskCanceled event added to the workflow history.
    A task is considered open from the time that it is scheduled until it is closed. Therefore a task is reported as open while a worker is processing it. A task is closed after it has been specified in a call to  RespondActivityTaskCompleted , RespondActivityTaskCanceled,  RespondActivityTaskFailed , or the task has timed out .
    Access Control
    You can use IAM policies to control this action's access to Amazon SWF resources as follows:
    If the caller does not have sufficient permissions to invoke the action, or the parameter values fall outside the specified constraints, the action fails. The associated event attribute's cause parameter will be set to OPERATION_NOT_PERMITTED. For details and example IAM policies, see Using IAM to Manage Access to Amazon SWF Workflows .
    See also: AWS API Documentation
    
    
    :example: response = client.respond_activity_task_canceled(
        taskToken='string',
        details='string'
    )
    
    
    :type taskToken: string
    :param taskToken: [REQUIRED]
            The taskToken of the ActivityTask .
            Warning
            taskToken is generated by the service and should be treated as an opaque value. If the task is passed to another process, its taskToken must also be passed. This enables it to provide its progress and respond with results.
            

    :type details: string
    :param details: Optional. Information about the cancellation.

    :returns: 
    taskToken (string) -- [REQUIRED]
    The taskToken of the  ActivityTask .
    
    Warning
    taskToken is generated by the service and should be treated as an opaque value. If the task is passed to another process, its taskToken must also be passed. This enables it to provide its progress and respond with results.
    
    
    details (string) -- Optional. Information about the cancellation.
    
    """
    pass
