docs: def dataset_update_method(dataset, other):
      """Guts of the Dataset.update method.
  
      This drops a duplicated coordinates from `other` if `other` is not an
      `xarray.Dataset`, e.g., if it's a dict with DataArray values (GH2068,
      GH2180).
      """
      from .dataset import Dataset
      from .dataarray import DataArray
  
      if not isinstance(other, Dataset):
          other = OrderedDict(other)
          for key, value in other.items():
              if isinstance(value, DataArray):
                  # drop conflicting coordinates
                  coord_names = [c for c in value.coords
                                 if c not in value.dims and c in dataset.coords]
                  if coord_names:
                      other[key] = value.drop(coord_names)
  
      return merge_core([dataset, other], priority_arg=1,
                        indexes=dataset.indexes)