def describe_hapg(HapgArn=None):
    """
    Retrieves information about a high-availability partition group.
    See also: AWS API Documentation
    
    
    :example: response = client.describe_hapg(
        HapgArn='string'
    )
    
    
    :type HapgArn: string
    :param HapgArn: [REQUIRED]
            The ARN of the high-availability partition group to describe.
            

    :rtype: dict
    :return: {
        'HapgArn': 'string',
        'HapgSerial': 'string',
        'HsmsLastActionFailed': [
            'string',
        ],
        'HsmsPendingDeletion': [
            'string',
        ],
        'HsmsPendingRegistration': [
            'string',
        ],
        'Label': 'string',
        'LastModifiedTimestamp': 'string',
        'PartitionSerialList': [
            'string',
        ],
        'State': 'READY'|'UPDATING'|'DEGRADED'
    }
    
    
    """
    pass
