def __init__(self, formatter, name, tags, hostname, device_name, extra_config=None):
        self.formatter = formatter
        self.name = name
        self.count = 0
        self.samples = []
        self.aggregates = extra_config['aggregates'] if\
            extra_config != None and extra_config.get('aggregates') is not None\
            else DEFAULT_HISTOGRAM_AGGREGATES
        self.percentiles = extra_config['percentiles'] if\
            extra_config is not None and extra_config.get('percentiles') is not None\
            else DEFAULT_HISTOGRAM_PERCENTILES
        self.tags = tags
        self.hostname = hostname
        self.device_name = device_name
        self.last_sample_time = None
dataset/ETHPy150Open serverdensity/sd-agent/aggregator.py/Histogram.__init__/operator `is not` -> `!=`