A company is opening a bank, but the coder who is designing the user class made some errors. They need  you  to help them. 
You must include the following:
- A withdraw method
  - Subtracts money from balance
  - One parameter, money to withdraw
  - Raise ValueError if there isn't enough money to withdraw
  - Return a string with name and balence(see examples)
* A check method
  - Adds money to baleance
  - Two parameters, other user and money
  - Other user will always be valid
  - Raise a ValueError if other user doesn't have enough money
  - Raise a ValueError if checking_account isn't true for other user
  - Return a string with name and balance plus other name and other balance(see examples)
- An add_cash method
  - Adds money to balance
  - One parameter, money to add
  - Return a string with name and balance(see examples)
Additional Notes:
  * Checking_account should be stored as a boolean
  - No input numbers will be negitive
  * Output must end with period
  - Float numbers will not be used so, balance should be integer
  * No currency will be used
Examples:
``` Python
Jeff = User('Jeff', 70, True)
Joe = User('Joe', 70, False)
Jeff.withdraw(2) # Returns 'Jeff has 68.'
Joe.check(Jeff, 50) # Returns 'Joe has 120 and Jeff has 18.'
Jeff.check(Joe, 80) # Raises a ValueError
Joe.checking_account = True # Enables checking for Joe
Jeff.check(Joe, 80) # Returns 'Jeff has 98 and Joe has 40'
Joe.check(Jeff, 100) # Raises a ValueError
Jeff.add_cash(20.00) # Returns 'Jeff has 118.'
```
 Good Luck

class User(object):
    def __init__(self, name, balance, checking_account):
        self.name = name
        self.balance = balance
        self.checking_account = checking_account

    def withdraw(self, amount):
        if amount > self.balance:
            raise ValueError
        self.balance -= amount
        return "{} has {}.".format(self.name, self.balance)

    def check(self, other, amount):
        if amount > other.balance or not other.checking_account:
            raise ValueError
        other.balance -= amount
        self.balance += amount
        return ( "{} has {} and {} has {}."
               .format(self.name, self.balance, other.name, other.balance) )

    def add_cash(self, amount):
        self.balance += amount
        return "{} has {}.".format(self.name, self.balance)


class User(object):
    def __init__(self, name, balance, checking_account):
        self.name = name
        self.balance = balance
        self.checking_account = checking_account

    def withdraw(self, amount):
        if amount > self.balance:
            raise ValueError
        self.balance -= amount
        return "{} has {}.".format(self.name, self.balance)

    def check(self, other, amount):
        if amount > other.balance or not other.checking_account:
            raise ValueError
        other.balance -= amount
        self.balance += amount
        return ( "{} has {} and {} has {}."
               .format(self.name, self.balance, other.name, other.balance) )

    def add_cash(self, amount):
        self.balance += amount
        return "{} has {}.".format(self.name, self.balance)
