v2 Diff remove duplicate elements

[MrSuNN]

a1 := []int{5, 5, 5}
a2 := []int{5, 5, 6}
added, removed := pie.Diff(a1, a2)
result is 
added: [5 6]
removed: [5 5]

view source because delete map,I don't understand why do this?

for _, s := range ss2raw {
	if _, ok := set[s]; ok {
		delete(set, s) // remove duplicates
	} else {
		result = append(result, s)
	}
}

Can't have repeating elements?
now I will use Unique and Diff together like this :pie.Diff(pie.Unique(a1), pie.Unique(a2))

[mohit-bhandari45]

do we need to change the function logic?

[elliotchance]

This does sound like a bug, happy to accept a PR to correctly handle duplicate values.