how does this work with customers being associated to accounts?

    >>> account1.email_address = 'a@b.c'; account1.save()
    >>> print customer1.email_address // customer1 is the representation of account1 via the customers endpoint
    'a@b.c'
    >>> customer1.email_address = 'b@b.c'; customer1.save()
    >>> print account1.email_address
    'b@b.c'
    >>> customer2.email_address = 'b@b.c'; customer2.save()
    >>> print account2.email_address
    ???