code: func IdentityFilterByProfileURL(profileURL string) func(db *gorm.DB) *gorm.DB {
  	return func(db *gorm.DB) *gorm.DB {
  		return db.Where("profile_url = ?", profileURL).Limit(1)
  	}
  }
docs: // IdentityFilterByProfileURL is a gorm filter by 'profile_url'