code: func IdentityFilterByRegistrationCompleted(registrationCompleted bool) func(db *gorm.DB) *gorm.DB {
  	return func(db *gorm.DB) *gorm.DB {
  		return db.Where("registration_completed = ?", registrationCompleted)
  	}
  }
docs: // IdentityFilterByRegistrationCompleted is a gorm filter by 'registration_completed'