[Matplotlib-users] Problem extending a custom colormap

[Damien I. <dam...@ya...>]

I often like to define my own colormaps using hex strings, e.g.
hex_list = ['#FFF295', '#FFD555', '#FF850B', '#D55000', '#D50000', '#550040', '#600080', '#000080', '#0000D5', '#0B85FF', '#55AAFF', '#95CAFF']
However, when I pass them to contourf and try to extend the colorbar... 
plt.contourf(x, y, data, colors=hex_list, extend='both')
... it always ends up that the color of the final segment on the extended ends of the colorbar is the same color as the extension segment (i.e. the bit in the little arrow). This happens even when hex_list is much longer than the actual number of segments required.
Has anyone else had this problem?