Surprised that guard clauses weren't mentioned here yet, you could also write ``` if (account == null) { throw NoAccountException } if (account.contact ==

Surprised that guard clauses weren't mentioned here yet, you could also write ``` if (account == null) { throw NoAccountException } if (account.contact == null) { throw AccountWithoutContactException } if (account.contact.phoneNumber == null) { throw ContactWithoutPhoneNumberException } // do stuff here ```