@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (!(o instanceof Person)) return false;

        Person person = (Person) o;

        if (!email.equals(person.email)) return false;
        if (!first_name.equals(person.first_name)) return false;
        if (!last_name.equals(person.last_name)) return false;

        return true;
    }