sub new {
    my $class = shift;
    my $name  = shift;
    my $self  = {
        NAME           => $name,
        CREDITAMOUNT   => Math::BigInt->new(0),
        DEBETAMOUNT    => Math::BigInt->new(0),
        CREDITACCOUNTS => [],
        DEBETACCOUNTS  => [],
    };
    my $closure = sub {
        my $field = shift;
        if (@_) { $self->{$field} = shift; }
        return $self->{$field};
    };
    bless( $closure, $class );
    return $closure;
}