diff --git a/parser.go b/parser.go
index 39f91f5..b0ff4f4 100644
--- a/parser.go
+++ b/parser.go
@@ -1,46 +1,54 @@
 package openwechat
 
 import (
-	"bytes"
-	"encoding/json"
-	"math/rand"
-	"net/http"
-	"strconv"
-	"strings"
-	"time"
+    "bytes"
+    "encoding/json"
+    "math/rand"
+    "net/http"
+    "strconv"
+    "strings"
+    "time"
 )
 
 func ToBuffer(v interface{}) (*bytes.Buffer, error) {
-	buf, err := json.Marshal(v)
-	if err != nil {
-		return nil, err
-	}
-	return bytes.NewBuffer(buf), nil
+    buf, err := json.Marshal(v)
+    if err != nil {
+        return nil, err
+    }
+    return bytes.NewBuffer(buf), nil
 }
 
 func GetRandomDeviceId() string {
-	rand.Seed(time.Now().Unix())
-	var builder strings.Builder
-	builder.WriteString("e")
-	for i := 0; i < 15; i++ {
-		r := rand.Intn(9)
-		builder.WriteString(strconv.Itoa(r))
-	}
-	return builder.String()
+    rand.Seed(time.Now().Unix())
+    var builder strings.Builder
+    builder.WriteString("e")
+    for i := 0; i < 15; i++ {
+        r := rand.Intn(9)
+        builder.WriteString(strconv.Itoa(r))
+    }
+    return builder.String()
 }
 
 func getWebWxDataTicket(cookies []*http.Cookie) string {
-	for _, cookie := range cookies {
-		if cookie.Name == "webwx_data_ticket" {
-			return cookie.Value
-		}
-	}
-	return ""
+    for _, cookie := range cookies {
+        if cookie.Name == "webwx_data_ticket" {
+            return cookie.Value
+        }
+    }
+    return ""
 }
 
 func XmlFormString(text string) string {
-	lt := strings.ReplaceAll(text, "&lt;", "<")
-	gt := strings.ReplaceAll(lt, "&gt;", ">")
-	br := strings.ReplaceAll(gt, "<br/>", "\n")
-	return strings.ReplaceAll(br, "&amp;amp;", "&")
+    lt := strings.ReplaceAll(text, "&lt;", "<")
+    gt := strings.ReplaceAll(lt, "&gt;", ">")
+    br := strings.ReplaceAll(gt, "<br/>", "\n")
+    return strings.ReplaceAll(br, "&amp;amp;", "&")
+}
+
+func getTotalDuration(delay ...time.Duration) time.Duration {
+    var total time.Duration
+    for _, d := range delay {
+        total += d
+    }
+    return total
 }
diff --git a/relations.go b/relations.go
index c415c9a..9aac6c1 100644
--- a/relations.go
+++ b/relations.go
@@ -104,10 +104,9 @@ func (f Friends) Search(limit int, condFuncList ...func(friend *Friend) bool) (r
 
 // 向slice的好友依次发送消息
 func (f Friends) SendMsg(msg *SendMessage, delay ...time.Duration) error {
+    total := getTotalDuration(delay...)
     for _, friend := range f {
-        if len(delay) != 0 {
-            time.Sleep(delay[0])
-        }
+        time.Sleep(total)
         if err := friend.SendMsg(msg); err != nil {
             return err
         }
@@ -117,10 +116,9 @@ func (f Friends) SendMsg(msg *SendMessage, delay ...time.Duration) error {
 
 // 向slice的好友依次发送文本消息
 func (f Friends) SendText(text string, delay ...time.Duration) error {
+    total := getTotalDuration(delay...)
     for _, friend := range f {
-        if len(delay) != 0 {
-            time.Sleep(delay[0])
-        }
+        time.Sleep(total)
         if err := friend.SendText(text); err != nil {
             return err
         }
@@ -130,10 +128,9 @@ func (f Friends) SendText(text string, delay ...time.Duration) error {
 
 // 向slice的好友依次发送图片消息
 func (f Friends) SendImage(file *os.File, delay ...time.Duration) error {
+    total := getTotalDuration(delay...)
     for _, friend := range f {
-        if len(delay) != 0 {
-            time.Sleep(delay[0])
-        }
+        time.Sleep(total)
         if err := friend.SendImage(file); err != nil {
             return err
         }
@@ -209,10 +206,7 @@ func (g Groups) Last() *Group {
 
 // 向群组依次发送消息, 支持发送延迟
 func (g Groups) SendMsg(msg *SendMessage, delay ...time.Duration) error {
-    var total time.Duration
-    for _, d := range delay {
-        total += d
-    }
+    total := getTotalDuration(delay...)
     for _, group := range g {
         time.Sleep(total)
         if err := group.SendMsg(msg); err != nil {
@@ -224,10 +218,7 @@ func (g Groups) SendMsg(msg *SendMessage, delay ...time.Duration) error {
 
 // 向群组依次发送文本消息, 支持发送延迟
 func (g Groups) SendText(text string, delay ...time.Duration) error {
-    var total time.Duration
-    for _, d := range delay {
-        total += d
-    }
+    total := getTotalDuration(delay...)
     for _, group := range g {
         time.Sleep(total)
         if err := group.SendText(text); err != nil {
@@ -239,10 +230,7 @@ func (g Groups) SendText(text string, delay ...time.Duration) error {
 
 // 向群组依次发送图片消息, 支持发送延迟
 func (g Groups) SendImage(file *os.File, delay ...time.Duration) error {
-    var total time.Duration
-    for _, d := range delay {
-        total += d
-    }
+    total := getTotalDuration(delay...)
     for _, group := range g {
         time.Sleep(total)
         if err := group.SendImage(file); err != nil {