Holding Objects Lab:

Fork and clone this repository to complete your lab. Submit each part with a Pull Request for a separate branch.

Unit Tests

Your completed lab must be submitted via GitHub.
Labs are not complete unless they include UML diagrams of all implemented classes, as well as unit tests for all features.

Create a PhoneBook class that holds names and phone numbers.
You can use an associative data type (one which stores items as keys paired with values).
Hint: You should use a sorted map.
Your PhoneBook class should have the following method
- hasEntry(String name)
  - given a name, return true if there is an entry with that name, false otherwise
- add(String name, String phoneNumber)
  - adds an entry to the composite associate data type
- lookup(String name)
  - returns a phone number for the respective input name
- remove(String name)
  - removes an entry to the composite associate data type
- reverseLookup(String phoneNumber)
  - returns a name for the respective input phoneNumber
- listNamesAndNumbers()
  - return a human-readable list of all entries (names and phone numbers) in alphabetical order.
  - Format should be [name] [phone number]
  - Sample Script
```
   PhoneBook phoneBook = new PhoneBook();
   phoneBook.add("Zebra", "111-222-333");
   phoneBook.add("Dog", "222-444-4444");
   phoneBook.listNamesAndNumbers();
```
  - Sample Output
```
    Dog 222-444-4444
    Zebra 111-222-333
```

Some people have more than one phone number.
Refactor your PhoneBook class to map names to lists of phone numbers.
You should modify your add() and remove() methods to handle adding or removing individual numbers
Create a removeRecord method for removing an entire entry from your PhoneBook.