Drop variables or index labels from this dataset.

        Parameters
        ----------
        labels : scalar or list of scalars
            Name(s) of variables or index labels to drop.
        dim : None or str, optional
            Dimension along which to drop index labels. By default (if
            ``dim is None``), drops variables rather than index labels.

        Returns
        -------
        dropped : Dataset

def drop(self, labels, dim=None):
        """Drop variables or index labels from this dataset.

        Parameters
        ----------
        labels : scalar or list of scalars
            Name(s) of variables or index labels to drop.
        dim : None or str, optional
            Dimension along which to drop index labels. By default (if
            ``dim is None``), drops variables rather than index labels.

        Returns
        -------
        dropped : Dataset
        """
        if utils.is_scalar(labels):
            labels = [labels]
        if dim is None:
            return self._drop_vars(labels)
        else:
            try:
                index = self.indexes[dim]
            except KeyError:
                raise ValueError(
                    'dimension %r does not have coordinate labels' % dim)
            new_index = index.drop(labels)
            return self.loc[{dim: new_index}]