diff --git a/go.mod b/go.mod
index ec69711..b02a7b4 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module qoobing.com/gomod/log
 
 go 1.16
+
+require qoobing.com/gomod/str v1.0.0
diff --git a/log.go b/log.go
index 0e534a0..686390d 100644
--- a/log.go
+++ b/log.go
@@ -9,19 +9,20 @@ import (
 	"log"
 	"os"
 	"path/filepath"
-	"qoobing.com/gomod/str"
 	"runtime"
 	"runtime/debug"
 	"strings"
 	"sync"
 	"time"
+
+	"qoobing.com/gomod/str"
 )
 
 var (
-	glogger  *log.Logger = nil
-	once     sync.Once   = sync.Once{}
-	mylogger *Logger     = nil
-    modellogs map[string]*Logger = map[string]*Logger{}
+	glogger   *log.Logger        = nil
+	once      sync.Once          = sync.Once{}
+	mylogger  *Logger            = nil
+	modellogs map[string]*Logger = map[string]*Logger{}
 )
 
 const ErrLogPanic = "~~~~panic~~~~~~"
@@ -63,9 +64,9 @@ func New(model string) (logger *Logger) {
 	if model == "" {
 		model = "undefine"
 	}
-	if _, ok := modellogs[model]; ok{
+	if _, ok := modellogs[model]; ok {
 		return modellogs[model]
-	}else{
+	} else {
 		modellogs[model] = &Logger{model: model, logger: glogger}
 		return modellogs[model]
 	}
@@ -250,7 +251,7 @@ func initlog() {
 
 					glogger = openlog(LOGFILENAME)
 					mylogger = New("system")
-					for _, l := range modellogs{
+					for _, l := range modellogs {
 						l.logger = glogger
 					}
 				}