code: def load_data_old(self):
          
          units = ""
          if len(self.file_objects) == 1 and self.file_objects[0] is not None:
              data = self.file_objects[0].variables[self.variable][self.forecast_hours]
              if hasattr(self.file_objects[0].variables[self.variable], "units"):
                  units = self.file_objects[0].variables[self.variable].units
          elif len(self.file_objects) > 1:
              grid_shape = [len(self.file_objects), 1, 1]
              for file_object in self.file_objects:
                  if file_object is not None:
                      if self.variable in file_object.variables.keys():
                          grid_shape = file_object.variables[self.variable].shape
                      elif self.variable.ljust(6, "_") in file_object.variables.keys():
                          grid_shape = file_object.variables[self.variable.ljust(6, "_")].shape
  
                      else:
                          print("{0} not found".format(self.variable))
                          raise KeyError
                      break
              data = np.zeros((len(self.file_objects), grid_shape[1], grid_shape[2]))
              for f, file_object in enumerate(self.file_objects):
                  if file_object is not None:
                      if self.variable in file_object.variables.keys():
                          var_name = self.variable
                      elif self.variable.ljust(6, "_") in file_object.variables.keys():
                          var_name = self.variable.ljust(6, "_")
                      else:
                          print("{0} not found".format(self.variable))
                          raise KeyError
                      data[f] = file_object.variables[var_name][0]
                      if units == "" and hasattr(file_object.variables[var_name], "units"):
                          units = file_object.variables[var_name].units
          else:
              data = None
          return data, units
docs: Loads time series of 2D data grids from each opened file. The code 
          handles loading a full time series from one file or individual time steps
          from multiple files. Missing files are supported.