docs: def stats(self, date=None):
          '''Return the current statistics for a given queue on a given date.
          The results are returned are a JSON blob::
  
              {
                  'total'    : ...,
                  'mean'     : ...,
                  'variance' : ...,
                  'histogram': [
                      ...
                  ]
              }
  
          The histogram's data points are at the second resolution for the first
          minute, the minute resolution for the first hour, the 15-minute
          resolution for the first day, the hour resolution for the first 3
          days, and then at the day resolution from there on out. The
          `histogram` key is a list of those values.'''
          return json.loads(
              self.client('stats', self.name, date or repr(time.time())))