code: def _load_from_disk(self, dtype_out_time, dtype_out_vert=False,
                          region=False):
          
          ds = xr.open_dataset(self.path_out[dtype_out_time])
          if region:
              arr = ds[region.name]
              # Use region-specific pressure values if available.
              if (self.dtype_in_vert == internal_names.ETA_STR
                      and not dtype_out_vert):
                  reg_pfull_str = region.name + '_pressure'
                  arr = arr.drop([r for r in arr.coords.iterkeys()
                                  if r not in (internal_names.PFULL_STR,
                                               reg_pfull_str)])
                  # Rename pfull to pfull_ref always.
                  arr = arr.rename({internal_names.PFULL_STR:
                                    internal_names.PFULL_STR + '_ref'})
                  # Rename region_pfull to pfull if its there.
                  if hasattr(arr, reg_pfull_str):
                      return arr.rename({reg_pfull_str:
                                         internal_names.PFULL_STR})
                  return arr
              return arr
          return ds[self.name]
docs: Load aospy data saved as netcdf files on the file system.