diff --git a/gee-rpc/day1-codec/codec/gob.go b/gee-rpc/day1-codec/codec/gob.go
index e4b2a67..d9ef2e6 100644
--- a/gee-rpc/day1-codec/codec/gob.go
+++ b/gee-rpc/day1-codec/codec/gob.go
@@ -41,15 +41,15 @@ func (c *GobCodec) Write(h *Header, body interface{}) (err error) {
 			_ = c.Close()
 		}
 	}()
-	if err := c.enc.Encode(h); err != nil {
-		log.Println("rpc codec: gob error encoding header:", err)
-		return err
+	if err = c.enc.Encode(h); err != nil {
+		log.Println("rpc: gob error encoding header:", err)
+		return
 	}
-	if err := c.enc.Encode(body); err != nil {
-		log.Println("rpc codec: gob error encoding body:", err)
-		return err
+	if err = c.enc.Encode(body); err != nil {
+		log.Println("rpc: gob error encoding body:", err)
+		return
 	}
-	return nil
+	return
 }
 
 func (c *GobCodec) Close() error {
diff --git a/gee-rpc/day2-client/codec/gob.go b/gee-rpc/day2-client/codec/gob.go
index e4b2a67..d9ef2e6 100644
--- a/gee-rpc/day2-client/codec/gob.go
+++ b/gee-rpc/day2-client/codec/gob.go
@@ -41,15 +41,15 @@ func (c *GobCodec) Write(h *Header, body interface{}) (err error) {
 			_ = c.Close()
 		}
 	}()
-	if err := c.enc.Encode(h); err != nil {
-		log.Println("rpc codec: gob error encoding header:", err)
-		return err
+	if err = c.enc.Encode(h); err != nil {
+		log.Println("rpc: gob error encoding header:", err)
+		return
 	}
-	if err := c.enc.Encode(body); err != nil {
-		log.Println("rpc codec: gob error encoding body:", err)
-		return err
+	if err = c.enc.Encode(body); err != nil {
+		log.Println("rpc: gob error encoding body:", err)
+		return
 	}
-	return nil
+	return
 }
 
 func (c *GobCodec) Close() error {
diff --git a/gee-rpc/day3-service/codec/gob.go b/gee-rpc/day3-service/codec/gob.go
index 808d97b..d9ef2e6 100644
--- a/gee-rpc/day3-service/codec/gob.go
+++ b/gee-rpc/day3-service/codec/gob.go
@@ -41,15 +41,15 @@ func (c *GobCodec) Write(h *Header, body interface{}) (err error) {
 			_ = c.Close()
 		}
 	}()
-	if err := c.enc.Encode(h); err != nil {
+	if err = c.enc.Encode(h); err != nil {
 		log.Println("rpc: gob error encoding header:", err)
-		return err
+		return
 	}
-	if err := c.enc.Encode(body); err != nil {
+	if err = c.enc.Encode(body); err != nil {
 		log.Println("rpc: gob error encoding body:", err)
-		return err
+		return
 	}
-	return nil
+	return
 }
 
 func (c *GobCodec) Close() error {
diff --git a/gee-rpc/day4-timeout/codec/gob.go b/gee-rpc/day4-timeout/codec/gob.go
index 808d97b..d9ef2e6 100644
--- a/gee-rpc/day4-timeout/codec/gob.go
+++ b/gee-rpc/day4-timeout/codec/gob.go
@@ -41,15 +41,15 @@ func (c *GobCodec) Write(h *Header, body interface{}) (err error) {
 			_ = c.Close()
 		}
 	}()
-	if err := c.enc.Encode(h); err != nil {
+	if err = c.enc.Encode(h); err != nil {
 		log.Println("rpc: gob error encoding header:", err)
-		return err
+		return
 	}
-	if err := c.enc.Encode(body); err != nil {
+	if err = c.enc.Encode(body); err != nil {
 		log.Println("rpc: gob error encoding body:", err)
-		return err
+		return
 	}
-	return nil
+	return
 }
 
 func (c *GobCodec) Close() error {
diff --git a/gee-rpc/day5-http-debug/codec/gob.go b/gee-rpc/day5-http-debug/codec/gob.go
index 808d97b..d9ef2e6 100644
--- a/gee-rpc/day5-http-debug/codec/gob.go
+++ b/gee-rpc/day5-http-debug/codec/gob.go
@@ -41,15 +41,15 @@ func (c *GobCodec) Write(h *Header, body interface{}) (err error) {
 			_ = c.Close()
 		}
 	}()
-	if err := c.enc.Encode(h); err != nil {
+	if err = c.enc.Encode(h); err != nil {
 		log.Println("rpc: gob error encoding header:", err)
-		return err
+		return
 	}
-	if err := c.enc.Encode(body); err != nil {
+	if err = c.enc.Encode(body); err != nil {
 		log.Println("rpc: gob error encoding body:", err)
-		return err
+		return
 	}
-	return nil
+	return
 }
 
 func (c *GobCodec) Close() error {
diff --git a/gee-rpc/day6-load-balance/codec/gob.go b/gee-rpc/day6-load-balance/codec/gob.go
index 808d97b..d9ef2e6 100644
--- a/gee-rpc/day6-load-balance/codec/gob.go
+++ b/gee-rpc/day6-load-balance/codec/gob.go
@@ -41,15 +41,15 @@ func (c *GobCodec) Write(h *Header, body interface{}) (err error) {
 			_ = c.Close()
 		}
 	}()
-	if err := c.enc.Encode(h); err != nil {
+	if err = c.enc.Encode(h); err != nil {
 		log.Println("rpc: gob error encoding header:", err)
-		return err
+		return
 	}
-	if err := c.enc.Encode(body); err != nil {
+	if err = c.enc.Encode(body); err != nil {
 		log.Println("rpc: gob error encoding body:", err)
-		return err
+		return
 	}
-	return nil
+	return
 }
 
 func (c *GobCodec) Close() error {
diff --git a/gee-rpc/day7-registry/codec/gob.go b/gee-rpc/day7-registry/codec/gob.go
index 808d97b..d9ef2e6 100644
--- a/gee-rpc/day7-registry/codec/gob.go
+++ b/gee-rpc/day7-registry/codec/gob.go
@@ -41,15 +41,15 @@ func (c *GobCodec) Write(h *Header, body interface{}) (err error) {
 			_ = c.Close()
 		}
 	}()
-	if err := c.enc.Encode(h); err != nil {
+	if err = c.enc.Encode(h); err != nil {
 		log.Println("rpc: gob error encoding header:", err)
-		return err
+		return
 	}
-	if err := c.enc.Encode(body); err != nil {
+	if err = c.enc.Encode(body); err != nil {
 		log.Println("rpc: gob error encoding body:", err)
-		return err
+		return
 	}
-	return nil
+	return
 }
 
 func (c *GobCodec) Close() error {