Colour palette in a Magics map

Hi

When using cdstoolbox.map.plot(...) to produce a Magics map, you can specify a colour palette, e.g. 'contour': 'eccharts_grey_red_20'

Is it possible to reverse this palette? For example, when using the palette "eccharts_green_blue_12" small values get a light (yellow) colour, while large values become dark (blue). Can I reverse this so that small values become dark and large values light? 

I'm hoping for a trick like in matplotlib, where you can add '_r' to get the reverse version of a colormap. 

Thanks!

Rutger