Misspelling in cairo_draw.py

When trying to set the colors for pie-chart-vertices, I got the folowing error:

File "/usr/lib/python3/dist-packages/graph_tool/draw/cairo_draw.py", line 379, in new_val = flatten(color_convert.to_rgba(x) for x in val) NameError: name 'color_convert' is not defined

There is no "color_convert" but "color_converter" in that file. Changing that line from

new_val = flatten(color_convert.to_rgba(x) for x in val)

to

new_val = flatten(color_converter.to_rgba(x) for x in val)

solved the issue on my local machine.