Malta IBAN parsing rules

Examples

    iex>  %IbanEx.Iban{
    ...>    country_code: "MT",
    ...>    check_digits: "84",
    ...>    bank_code: "MALT",
    ...>    branch_code: "01100",
    ...>    national_check: nil,
    ...>    account_number: "0012345MTLCAST001S"
    ...>  }
    ...>  |> IbanEx.Country.MT.to_string()
    "MT 84 MALT 01100 0012345MTLCAST001S"