code: def _calculate_period(self, vals):
          ''' calculate the sampling period in seconds '''
          if len(vals) < 4:
              return None
  
          if self.firmware['major'] < 16:
              return ((vals[3] << 24) | (vals[2] << 16) | (vals[1] << 8) | vals[0]) / 12e6
          else:
              return self._calculate_float(valsf _calculate_period(self, vals):
          ''' calculate the sampling period in seconds '''
          if len(vals) < 4:
              return None
  
          if self.firmware['major'] < 16:
              return ((vals[3] << 24) | (vals[2] << 16) | (vals[1] << 8) | vals[0]) / 12e6
          else:
              return self._calculate_float(vals)
docs: calculate the sampling period in seconds