def describe_cache(GatewayARN=None):
    """
    Returns information about the cache of a gateway. This operation is only supported in the cached volume,tape and file gateway architectures.
    The response includes disk IDs that are configured as cache, and it includes the amount of cache allocated and used.
    See also: AWS API Documentation
    
    Examples
    Returns information about the cache of a gateway.
    Expected Output:
    
    :example: response = client.describe_cache(
        GatewayARN='string'
    )
    
    
    :type GatewayARN: string
    :param GatewayARN: [REQUIRED]
            The Amazon Resource Name (ARN) of the gateway. Use the ListGateways operation to return a list of gateways for your account and region.
            

    :rtype: dict
    :return: {
        'GatewayARN': 'string',
        'DiskIds': [
            'string',
        ],
        'CacheAllocatedInBytes': 123,
        'CacheUsedPercentage': 123.0,
        'CacheDirtyPercentage': 123.0,
        'CacheHitPercentage': 123.0,
        'CacheMissPercentage': 123.0
    }
    
    
    """
    pass
