diff --git a/util/rev_sec.go b/util/rev_sec.go
deleted file mode 100644
index 281159d..0000000
--- a/util/rev_sec.go
+++ /dev/null
@@ -1,52 +0,0 @@
-package util
-
-import (
-	"sort"
-	"strings"
-)
-
-type ReverseSecSlice struct {
-	sort.StringSlice
-}
-
-func NewReverseSecSlice(a []string) *ReverseSecSlice {
-	return &ReverseSecSlice{sort.StringSlice(a)}
-}
-
-func (p *ReverseSecSlice) Sort() *ReverseSecSlice {
-	sort.Sort(p)
-	return p
-}
-func (p *ReverseSecSlice) Uniq() []string {
-	olds := []string(p.StringSlice)
-
-	last := ""
-	strs := make([]string, 0, len(olds))
-	for _, str := range olds {
-		if str != last {
-			strs = append(strs, str)
-		}
-		last = str
-	}
-	return strs
-}
-
-func (p *ReverseSecSlice) Less(i, j int) bool {
-	secsI := strings.Split(p.StringSlice[i], ".")
-	secsJ := strings.Split(p.StringSlice[j], ".")
-
-	lenI := len(secsI) - 1
-	lenJ := len(secsJ) - 1
-	length := lenI
-	if lenI > lenJ {
-		length = lenJ
-	}
-
-	for idx := 0; idx <= length; idx++ {
-		if secsI[lenI-idx] == secsJ[lenJ-idx] {
-			continue
-		}
-		return secsI[lenI-idx] < secsJ[lenJ-idx]
-	}
-	return lenI < lenJ
-}
diff --git a/util/rev_sec_test.go b/util/rev_sec_test.go
deleted file mode 100644
index 5946250..0000000
--- a/util/rev_sec_test.go
+++ /dev/null
@@ -1,65 +0,0 @@
-package util
-
-import (
-	"sort"
-	"testing"
-)
-
-func TestReverseSecSlice_Less(t *testing.T) {
-	type fields struct {
-		StringSlice sort.StringSlice
-	}
-	type args struct {
-		i int
-		j int
-	}
-	slice := fields{sort.StringSlice([]string{
-		"a.b.c",
-		"a.b.c",
-		"d.b.c",
-		"d.a.b.c",
-		"",
-		"",
-	})}
-	tests := []struct {
-		name   string
-		fields fields
-		args   args
-		want   bool
-	}{{
-		name:   "equal",
-		fields: slice,
-		args:   args{0, 1},
-		want:   false,
-	}, {
-		name:   "less",
-		fields: slice,
-		args:   args{0, 2},
-		want:   true,
-	}, {
-		name:   "length",
-		fields: slice,
-		args:   args{0, 3},
-		want:   true,
-	}, {
-		name:   "single_empty",
-		fields: slice,
-		args:   args{0, 4},
-		want:   false,
-	}, {
-		name:   "all_empty",
-		fields: slice,
-		args:   args{4, 5},
-		want:   false,
-	}}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			p := &ReverseSecSlice{
-				StringSlice: tt.fields.StringSlice,
-			}
-			if got := p.Less(tt.args.i, tt.args.j); got != tt.want {
-				t.Errorf("ReverseSecSlice.Less() = %v, want %v", got, tt.want)
-			}
-		})
-	}
-}