docs: def set_features(self, partition=1):
          """ Parses market data JSON for technical analysis indicators
  
          Args:
              partition: Int of how many dates to take into consideration
                  when evaluating technical analysis indicators.
  
          Returns:
              Pandas DataFrame instance with columns as numpy.float32 features.
          """
          if len(self.json) < partition + 1:
              raise ValueError('Not enough dates for the specified partition size: {0}.  Try a smaller partition.'.format(partition))
  
          data = []
          for offset in range(len(self.json) - partition):
              json = self.json[offset : offset + partition]
              data.append(eval_features(json))
          return pd.DataFrame(data=data, dtype=np.float32)