st: Pie Chart Color Scheme

[jasonm@ucla.edu]

I have four pie charts that I generate using

graph pie, over(dogs)

One of the pie charts has four groups while the other pie charts have  
five groups (the group with four has zero for one of its levels of the  
"dog" variable).
How can I create a unified color scheme where a is always red, b is  
always blue, c is always yellow, d is always green, and e is always  
purple for the four pie charts (ie if one of the levels is missing  
then legend gets modified)?
Thanks,
Jason
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