def map_dataarray(self, func, x, y, **kwargs):
        """
        Apply a plotting function to a 2d facet's subset of the data.

        This is more convenient and less general than ``FacetGrid.map``

        Parameters
        ----------
        func : callable
            A plotting function with the same signature as a 2d xarray
            plotting method such as `xarray.plot.imshow`
        x, y : string
            Names of the coordinates to plot on x, y axes
        kwargs :
            additional keyword arguments to func

        Returns
        -------
        self : FacetGrid object

        """
        # These should be consistent with xarray.plot._plot2d
        cmap_kwargs = {'plot_data': self.data.values,
                       # MPL default
                       'levels': 7 if func.__name__ in 'contour' else None,
                       'filled': func.__name__ != 'contour',
                       }

        cmap_args = inspect.getargspec(_determine_cmap_params).args
        cmap_kwargs.update((a, kwargs[a]) for a in cmap_args if a in kwargs)

        cmap_params = _determine_cmap_params(**cmap_kwargs)

        # Order is important
        func_kwargs = kwargs.copy()
        func_kwargs.update(cmap_params)
        func_kwargs.update({'add_colorbar': False, 'add_labels': False})

        # Get x, y labels for the first subplot
        x, y = _infer_xy_labels(darray=self.data.loc[self.name_dicts.flat[0]],
                                x=x, y=y)

        for d, ax in zip(self.name_dicts.flat, self.axes.flat):
            # None is the sentinel value
            if d is not None:
                subset = self.data.loc[d]
                mappable = func(subset, x, y, ax=ax, **func_kwargs)
                self._mappables.append(mappable)

        self._cmap_extend = cmap_params.get('extend')
        self._finalize_grid(x, y)

        if kwargs.get('add_colorbar', True):
            self.add_colorbar()

        return self
dataset/ETHPy150Open pydata/xarray/xarray/plot/facetgrid.py/FacetGrid.map_dataarray/swapped operands of `in`