feat: improvements in entity domain logic

domain/usecase/book/mock/book.go

@@ -5,10 +5,9 @@
 package mock
 
 import (
-	reflect "reflect"
-
 	entity "github.com/eminetto/clean-architecture-go-v2/domain/entity"
 	gomock "github.com/golang/mock/gomock"
+	reflect "reflect"
 )
 
 // MockReader is a mock of Reader interface

domain/usecase/book/service.go

@@ -27,10 +27,6 @@ func (s *Service) CreateBook(title string, author string, pages int, quantity in
 	if err != nil {
 		return b.ID, err
 	}
-	err = b.Validate()
-	if err != nil {
-		return b.ID, err
-	}
 	return s.repo.Create(b)
 }