```
curve(dpert(x, min=3, mode=5, max=10, shape=6), from = 2, to = 11, lty=3)
curve(dpert(x, min=3, mode=5, max=10), from = 2, to = 11, add=TRUE)
curve(dpert(x, min=3, mode=5, max=10, shape=2), from = 2, to = 11, add=TRUE, lty=2)
legend(x = 8, y = 2, c("Default", "shape:2", "shape:6"), lty=1:3)
```

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