```ruby
require('rspec')
require('contact_phone_number')

describe(ContactPhoneNumber) do
  describe('#initialize') do
    it('is empty at first') do
      test_phone_number = ContactPhoneNumber.new({:phone_number => nil})
      expect(ContactPhoneNumber.all()).to(eq([]))
    end
  end
  describe('#save') do
    it('saves the phone number and returns it') do
      test_number = ContactPhoneNumber.new({:phone_number => '5125676637'})
      test_number.save()
      expect(ContactPhoneNumber.all()).to(eq('5125675537'))
    end
  end
end
```

Add contact phone number save spec and method
user
```ruby
require('rspec')
require('contact_phone_number')

describe(ContactPhoneNumber) do
  describe('#initialize') do
    it('is empty at first') do
      test_phone_number = ContactPhoneNumber.new({:phone_number => nil})
      expect(ContactPhoneNumber.all()).to(eq([]))
    end
  end
  describe('#save') do
    it('saves the phone number and returns it') do
      test_number = ContactPhoneNumber.new({:phone_number => '5125676637'})
      test_number.save()
      expect(ContactPhoneNumber.all()).to(eq([test_number]))
    end
  end
end
```
assistant