docs: def get_json(self):
          """ Gets market chart data from today to a previous date """
          today = dt.now()
          DIRECTION = 'last'
          epochs = date.get_end_start_epochs(today.year, today.month, today.day,
                                             DIRECTION, self.unit, self.count)
          return poloniex.chart_json(epochs['shifted'], epochs['initial'],
                                     self.period, self.symbol)[0]