dpplot is not a twoway plot type

[Paula TH]

Hi!
I'm using dpplot in Stata 18 from ssc. I am generating 5 different dpplots and wanted to display them in a single graph with each pdf having a different color and identify them in the legend. However, the error message says "dpplot is not a twoway plot type". Is there any way around this?
Thanks

[Paula TH]

For anyone wondering, this is apparently as good as it gets:

forvalues i=1/5 {
sum var if category==`i'
local m`i' = r(mean)
local SD`i' = r(sd)
local min`i' = r(min)
local max`i' = r(max)
}

twoway function var = normalden(x, `m1', `SD1'), ra(`min1' `max1') || ///
function var = normalden(x, `m2', `SD2'), ra(`min2' `max2') || ///
function var = normalden(x, `m3', `SD3'), ra(`min3' `max3') || ///
function var = normalden(x, `m4', `SD4'), ra(`min4' `max4') || ///
function var = normalden(x, `m5', `SD5'), ra(`min5' `max5') ///
legend( position(6) cols(5)) ytitle(Density)