`InternalLoan` MUST exist at least once. `InternalLoan` MUST exist at least once. `InternalLoan` MUST exist at least once. `InternalLoan` MUST exist at least once. `InternalLoan` MUST exist at least once. `InternalLoan` MUST exist at least once. `InternalLoan` at beginning of the current period MUST exist at least once. `InternalLoan` at end of period MUST be equal to `InternalLoan` at beginning of period - `Redemption` + `Contribution`. `Redemption` for the current period MUST exist at least once. `Redemption` for the fifth period MUST exist at least once. `Redemption` for the first period MUST exist at least once. `Redemption` for the fourth period MUST exist at least once. `Redemption` for the second period MUST exist at least once. `Redemption` for the third period MUST exist at least once.