diff --git a/cli/papero/set.go b/cli/papero/set.go
index e95e1a6..be6f068 100644
--- a/cli/papero/set.go
+++ b/cli/papero/set.go
@@ -1,7 +1,6 @@
 package main
 
 import (
-	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -51,57 +50,6 @@ func (s SetCmd) Help(w io.Writer, set *flag.FlagSet) {
 	}
 }
 
-// FLAG UTILS
-
-type pair struct {
-	set, unset bool
-}
-
-type pairFlag struct {
-	*pair
-}
-
-func newPairFlag() pairFlag {
-	return pairFlag{
-		&pair{false, false},
-	}
-}
-
-func (p pair) String() string {
-	switch p {
-	case pair{true, false}:
-		return "set"
-	case pair{false, true}:
-		return "unset"
-	default:
-		return "undef"
-	}
-}
-
-func (pf pairFlag) String() string {
-	return pf.pair.String()
-}
-
-func (pf pairFlag) Set(s string) error {
-	Log.Debugf("into Set: %s\n", s)
-	if s == "set" {
-		Log.Debug("setting")
-		v := pair{true, false}
-		*pf.pair = v
-		return nil
-	}
-
-	if s == "unset" {
-		Log.Debug("unsetting")
-		v := pair{false, true}
-		*pf.pair = v
-		return nil
-	}
-
-	Log.Debug(fmt.Sprintf("unacceptable value %s\n", s))
-	return errors.New("only `set` or `unset` are allowed")
-}
-
 // VERBS
 
 type SetMessageCmd struct{}
@@ -112,11 +60,11 @@ func (sm SetMessageCmd) Func(args []string) error {
 	}
 	flags := imaputils.NewFlagsStatus()
 	var opts imaputils.SetFlagsOpts
-	flagSeen := newPairFlag()
-	flagAnswered := newPairFlag()
-	flagFlagged := newPairFlag()
-	flagDeleted := newPairFlag()
-	flagDraft := newPairFlag()
+	flagSeen := cli.NewPairFlag()
+	flagAnswered := cli.NewPairFlag()
+	flagFlagged := cli.NewPairFlag()
+	flagDeleted := cli.NewPairFlag()
+	flagDraft := cli.NewPairFlag()
 
 	flagset := flag.NewFlagSet(args[0], flag.ExitOnError)
 
@@ -148,19 +96,19 @@ func (sm SetMessageCmd) Func(args []string) error {
 	opts.MessageSeq = seq
 	opts.Debug = Session.Info.Opts.Debug
 
-	if err := assignFlag(*flagSeen.pair, flags.SetSeen, flags.UnsetSeen); err != nil {
+	if err := assignFlag(*flagSeen.Pair, flags.SetSeen, flags.UnsetSeen); err != nil {
 		return err
 	}
-	if err := assignFlag(*flagAnswered.pair, flags.SetAnswered, flags.UnsetAnswered); err != nil {
+	if err := assignFlag(*flagAnswered.Pair, flags.SetAnswered, flags.UnsetAnswered); err != nil {
 		return err
 	}
-	if err := assignFlag(*flagFlagged.pair, flags.SetFlagged, flags.UnsetFlagged); err != nil {
+	if err := assignFlag(*flagFlagged.Pair, flags.SetFlagged, flags.UnsetFlagged); err != nil {
 		return err
 	}
-	if err := assignFlag(*flagDeleted.pair, flags.SetDeleted, flags.UnsetDeleted); err != nil {
+	if err := assignFlag(*flagDeleted.Pair, flags.SetDeleted, flags.UnsetDeleted); err != nil {
 		return err
 	}
-	if err := assignFlag(*flagDraft.pair, flags.SetDraft, flags.UnsetDraft); err != nil {
+	if err := assignFlag(*flagDraft.Pair, flags.SetDraft, flags.UnsetDraft); err != nil {
 		return err
 	}
 
@@ -202,11 +150,11 @@ func parseMessageSeq(seq *imap.SeqSet, data string) error {
 	return nil
 }
 
-func assignFlag(flagOp pair, setCallback, unsetCallback func()) error {
+func assignFlag(flagOp cli.Pair, setCallback, unsetCallback func()) error {
 	switch flagOp {
-	case pair{true, false}:
+	case cli.Pair{true, false}:
 		setCallback()
-	case pair{false, true}:
+	case cli.Pair{false, true}:
 		unsetCallback()
 	default:
 		return nil
diff --git a/cli/utils.go b/cli/utils.go
index d808595..4edd324 100644
--- a/cli/utils.go
+++ b/cli/utils.go
@@ -1,6 +1,7 @@
 package cli
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"io"
@@ -36,3 +37,50 @@ func Usage(w io.Writer, info ProgramInfo) {
 		fmt.Fprintf(w, "\t%s\n", command)
 	}
 }
+
+type Pair struct {
+	Set, Unset bool
+}
+
+type PairFlag struct {
+	*Pair
+}
+
+func NewPairFlag() PairFlag {
+	return PairFlag{
+		&Pair{false, false},
+	}
+}
+
+func (p Pair) String() string {
+	switch p {
+	case Pair{true, false}:
+		return "set"
+	case Pair{false, true}:
+		return "unset"
+	default:
+		return "undef"
+	}
+}
+
+func (pf PairFlag) String() string {
+	return pf.Pair.String()
+}
+
+func (pf PairFlag) Set(s string) error {
+	if s == "set" {
+		v := Pair{true, false}
+		*pf.Pair = v
+		return nil
+	}
+
+	if s == "unset" {
+		v := Pair{false, true}
+		*pf.Pair = v
+		return nil
+	}
+
+	return ErrAllowedPairFlagValues
+}
+
+var ErrAllowedPairFlagValues = errors.New("only `set` or `unset` are allowed")