Problem 7

Create methods for BankAccount, FedexAccount and KazPostAccount. From BankAccount and KazPostAccount can be withdrawn money. From FedexAccount and KazPostAccount can be sent packages.

normanOsborne := BankAccount{
    name:    "Norman Osborne",
    balance: 1_000_000,
}
peterParker := FedexAccount{
    name: "Peter Parker",
	packages: make(string[])
}
auntMay := KazPostAccount{
    name:    "Aunt May",
    balance: 200,
	packages: make(string[])
}

withdrawMoney(10, normanOsborne, auntMay) // can be withdrawn by multiple people
sendPackagesTo("Mary Jane", peterParker, auntMay) // can be sent by multiple people