code: def load_data_file(self, fname, filemode='a'):
          
          self.close_data()
          self.datafile = open_acqdata(fname, filemode=filemode)
  
          self.explorer.set(datafile=self.datafile)
          self.protocoler.set(datafile=self.datafile)
          self.charter.set(datafile=self.datafile)
          self.bs_calibrator.set(datafile=self.datafile)
          self.tone_calibrator.set(datafile=self.datafile)
          self.set_calibration(None)
  
          self.current_cellid = dict(self.datafile.get_info('')).get('total cells', 0)
docs: Opens an existing data file to append to
  
          :param fname: File path of the location for the data file to open
          :type fname: str