def describe_activity(activityArn=None):
    """
    Describes an activity.
    See also: AWS API Documentation
    
    
    :example: response = client.describe_activity(
        activityArn='string'
    )
    
    
    :type activityArn: string
    :param activityArn: [REQUIRED]
            The Amazon Resource Name (ARN) of the activity to describe.
            

    :rtype: dict
    :return: {
        'activityArn': 'string',
        'name': 'string',
        'creationDate': datetime(2015, 1, 1)
    }
    
    
    """
    pass
