# private getCreditAccounts
sub getCreditAccounts {
    caller(0) eq __PACKAGE__ || confess "getCreditAccounts is private";
    my $closure = shift;
    my @accounts = @{ &{$closure}( "CREDITACCOUNTS" ) };
    return @accounts;
}

# working on a copy of the original array...
my @anotherArray = $obj->getCreditAccounts();
push @anotherArray, "Data";