guess the second coordinate when only one is passed to pcolormesh()

[vnoel]

Say I have a DataArray z with dimensions ('x', 'y'), in that order. If I call z.plot(), it will create a pcolormesh with x the vertical dimension and y the horizontal one. If I want to invert the axes, I need to call z.plot(x='x', y='y'). If I supply only one of the dimensions, i.e. z.plot(x='x'), I get the error message

ValueError: cannot supply only one of x and y

I think that when calling the plot function on a 2d DataArray and passing only one coordinate, as in z.plot(x='x'), xarray could guess we want the unpassed coordinate to be the other one. I don't see why this would be unsafe.