@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;

        Person person1 = (Person) o;

        if (age != person1.age) return false;
        if (firstName != null ? !firstName.equals(person1.firstName) : person1.firstName != null) return false;
        if (lastName != null ? !lastName.equals(person1.lastName) : person1.lastName != null) return false;

        return true;
    }