def METHOD_NAME(spec, state, indices, out_epochs):
    total_slashed_balance = 0
    for i, out_epoch in zip(indices, out_epochs):
        v = state.validators[i]
        v.slashed = True
        spec.initiate_validator_exit(state, i)
        v.withdrawable_epoch = out_epoch
        total_slashed_balance += v.effective_balance
    state.slashings[
        spec.get_current_epoch(state) % spec.EPOCHS_PER_SLASHINGS_VECTOR
    ] = total_slashed_balance
    # verify some slashings happened...
    assert total_slashed_balance != 0