diff --git a/example/main.go b/example/main.go
index 1180daf..7307ad2 100644
--- a/example/main.go
+++ b/example/main.go
@@ -23,19 +23,18 @@ func main() {
 	// Get a topic list
 	topics := topic.Topics()
 
-	for i, v := range topics.Topics {
-		r := fmt.Sprintf("index:/%d/ - value:/%s/ ", i, v)
-		fmt.Println(r)
+	for _, v := range topics.Topics {
+		fmt.Println(v)
 	}
 
 	// Create a new subscription
-	topic.CreateSubscription(topicName,subName)
+	topic.CreateSubscription(topicName, subName)
 
 	// Get subscriptions
 	topic.Subscriptions(topicName)
 
 	// Publish a new message
-	topic.Publish(topicName,"Fly me to the moon..")
+	topic.Publish(topicName, "Fly me to the moon..")
 
 	// Get message to sub
 	topic.Receive(subName)
diff --git a/internal/error/clienterr/client.go b/internal/error/clienterr/client.go
index 3dc87c3..86da33f 100644
--- a/internal/error/clienterr/client.go
+++ b/internal/error/clienterr/client.go
@@ -2,4 +2,5 @@ package clienterr
 
 import "errors"
 
-var ClientCannotCreate = errors.New("client can not create")
+// ErrClientCannotCreate err
+var ErrClientCannotCreate = errors.New("client can not create")
diff --git a/internal/error/convererr/conver.go b/internal/error/convererr/conver.go
index a802243..8df22c0 100644
--- a/internal/error/convererr/conver.go
+++ b/internal/error/convererr/conver.go
@@ -2,4 +2,5 @@ package convererr
 
 import "errors"
 
-var JsonMarshalCanNotBeParse = errors.New("json marshal can not be parse")
+// ErrJsonMarshalCanNotBeParse err
+var ErrJsonMarshalCanNotBeParse = errors.New("json marshal can not be parse")
diff --git a/internal/error/topicerr/topic.go b/internal/error/topicerr/topic.go
index 64cca9d..b3b3dee 100644
--- a/internal/error/topicerr/topic.go
+++ b/internal/error/topicerr/topic.go
@@ -2,8 +2,17 @@ package topicerr
 
 import "errors"
 
-var TopicCanNotCreate = errors.New("topic can not create")
-var TopicDoExist = errors.New("topic do exist")
-var TopicDoNotExist = errors.New("topic do not exist")
-var TopicCanNotExists = errors.New("topic does not exist")
-var TopicCanNotDelete = errors.New("topic can not delete")
+// ErrTopicCanNotCreate err
+var ErrTopicCanNotCreate = errors.New("topic can not create")
+
+// ErrTopicDoExist err
+var ErrTopicDoExist = errors.New("topic do exist")
+
+// ErrTopicDoNotExist err
+var ErrTopicDoNotExist = errors.New("topic do not exist")
+
+// ErrTopicCanNotExists err
+var ErrTopicCanNotExists = errors.New("topic does not exist")
+
+// ErrTopicCanNotDelete err
+var ErrTopicCanNotDelete = errors.New("topic can not delete")
diff --git a/internal/model/response/topicres/topics.go b/internal/model/response/topicres/topics.go
index 677f89f..abb79d7 100644
--- a/internal/model/response/topicres/topics.go
+++ b/internal/model/response/topicres/topics.go
@@ -1,5 +1,6 @@
 package topicres
 
+// TopicsModel is a struct
 type TopicsModel struct {
 	Topics []string
 }
diff --git a/pkg/client/client.go b/pkg/client/client.go
index 78c7cd8..08bc076 100644
--- a/pkg/client/client.go
+++ b/pkg/client/client.go
@@ -19,7 +19,7 @@ func Create(clientId string) (Client, context.Context, error) {
 	c, err := pubsub.NewClient(ctx, clientId)
 
 	if err != nil {
-		err = clienterr.ClientCannotCreate
+		err = clienterr.ErrClientCannotCreate
 	}
 
 	client := Client{
diff --git a/pkg/topic/topic.go b/pkg/topic/topic.go
index b2aba12..95f70f1 100644
--- a/pkg/topic/topic.go
+++ b/pkg/topic/topic.go
@@ -33,22 +33,22 @@ func Create(topicName string) error {
 	defer client.Close(c)
 
 	if err != nil {
-		return clienterr.ClientCannotCreate
+		return clienterr.ErrClientCannotCreate
 	}
 
 	e := c.Client.Topic(topicName)
 	ok, err := e.Exists(ctx)
 	if err != nil {
-		return topicerr.TopicCanNotExists
+		return topicerr.ErrTopicCanNotExists
 	}
 	if ok {
-		return topicerr.TopicDoExist
+		return topicerr.ErrTopicDoExist
 	}
 
 	topic, err := c.Client.CreateTopic(ctx, topicName)
 
 	if err != nil {
-		return topicerr.TopicCanNotCreate
+		return topicerr.ErrTopicCanNotCreate
 	}
 
 	defer topic.Stop()
@@ -64,16 +64,15 @@ func Delete(topicName string) (bool, error) {
 	defer client.Close(c)
 
 	if err != nil {
-		return false, clienterr.ClientCannotCreate
+		return false, clienterr.ErrClientCannotCreate
 	}
 
 	topic := c.Client.Topic(topicName)
 	defer topic.Stop()
 	if err := topic.Delete(ctx); err != nil {
-		return false, topicerr.TopicCanNotDelete
-	} else {
-		return true, nil
+		return false, topicerr.ErrTopicCanNotDelete
 	}
+	return true, nil
 }
 
 // Exists topic control in project
@@ -84,7 +83,7 @@ func Exists(topicName string) (bool, error) {
 	defer client.Close(c)
 
 	if err != nil {
-		return false, clienterr.ClientCannotCreate
+		return false, clienterr.ErrClientCannotCreate
 	}
 
 	e := c.Client.Topic(topicName)
@@ -101,7 +100,7 @@ func Topics() topicres.TopicsModel {
 	defer client.Close(c)
 
 	if err != nil {
-		log.Println(clienterr.ClientCannotCreate)
+		log.Println(clienterr.ErrClientCannotCreate)
 		return topics
 	}
 
@@ -129,7 +128,7 @@ func CreateSubscription(topicName string, subName string) {
 	defer client.Close(c)
 
 	if err != nil {
-		log.Println(clienterr.ClientCannotCreate)
+		log.Println(clienterr.ErrClientCannotCreate)
 		return
 	}
 
@@ -139,7 +138,7 @@ func CreateSubscription(topicName string, subName string) {
 		return
 	}
 	if !exist {
-		log.Println(topicerr.TopicDoNotExist)
+		log.Println(topicerr.ErrTopicDoNotExist)
 		return
 	}
 
@@ -169,7 +168,7 @@ func Subscriptions(topicName string) {
 	defer client.Close(c)
 
 	if err != nil {
-		log.Println(clienterr.ClientCannotCreate)
+		log.Println(clienterr.ErrClientCannotCreate)
 	}
 
 	topic := c.Client.Topic(topicName)
@@ -199,7 +198,7 @@ func Publish(topicName string, message interface{}) (bool, error) {
 	defer client.Close(c)
 
 	if err != nil {
-		return false, clienterr.ClientCannotCreate
+		return false, clienterr.ErrClientCannotCreate
 	}
 
 	topic := c.Client.Topic(topicName)
@@ -208,7 +207,7 @@ func Publish(topicName string, message interface{}) (bool, error) {
 
 	m, err := json.Marshal(message)
 	if err != nil {
-		return false, convererr.JsonMarshalCanNotBeParse
+		return false, convererr.ErrJsonMarshalCanNotBeParse
 	}
 
 	var results []*pubsub.PublishResult