diff --git a/convert.go b/convert.go
index db27ea3..5a80ddb 100644
--- a/convert.go
+++ b/convert.go
@@ -1,18 +1,11 @@
 package mongodb
 
 import (
-	"encoding/json"
 	"github.com/thoas/go-funk"
 	"go.mongodb.org/mongo-driver/bson/primitive"
 	"sort"
 )
 
-// GetAppIDFromHex ...
-func GetAppIDFromHex(s string) primitive.ObjectID {
-	id, _ := primitive.ObjectIDFromHex(s)
-	return id
-}
-
 // ConvertObjectIDsToStrings ...
 func ConvertObjectIDsToStrings(ids []primitive.ObjectID) []string {
 	return funk.Map(ids, func(item primitive.ObjectID) string {
@@ -30,7 +23,7 @@ func UniqObjectIds(ids []primitive.ObjectID) []primitive.ObjectID {
 // ConvertStringsToObjectIDs ...
 func ConvertStringsToObjectIDs(strValues []string) []primitive.ObjectID {
 	return funk.Map(strValues, func(item string) primitive.ObjectID {
-		return GetAppIDFromHex(item)
+		return ConvertStringToObjectID(item)
 	}).([]primitive.ObjectID)
 }
 
@@ -47,36 +40,3 @@ func SortObjectId(ids []primitive.ObjectID) []primitive.ObjectID {
 	})
 	return ids
 }
-
-// ConvertInterfacesToObjectIDs ...
-func ConvertInterfacesToObjectIDs(values []interface{}) []primitive.ObjectID {
-	s := make([]primitive.ObjectID, len(values))
-	for i, v := range values {
-		s[i] = v.(primitive.ObjectID)
-	}
-	return s
-}
-
-// ConvertInterfacesToStrings ...
-func ConvertInterfacesToStrings(values []interface{}) []string {
-	s := make([]string, len(values))
-	for i, v := range values {
-		s[i] = v.(string)
-	}
-	return s
-}
-
-// ConvertStringsToInterfaces ...
-func ConvertStringsToInterfaces(values []string) []interface{} {
-	s := make([]interface{}, len(values))
-	for _, v := range values {
-		s = append(s, v)
-	}
-	return s
-}
-
-// ConvertToJSONString ...
-func ConvertToJSONString(data interface{}) string {
-	dataByte, _ := json.Marshal(data)
-	return string(dataByte)
-}