my $config = AppConfig->new( {
            CASE   => 1,
            ERROR  => \&my_error,
            GLOBAL => { 
                    DEFAULT  => "<unset>", 
                    ARGCOUNT => ARGCOUNT_ONE,
                },
        } );

##</code><code>##

my $config = AppConfig->new( {
            CASE   => 1,
            ERROR  => hanlde_errors(),
            GLOBAL => { 
                    DEFAULT  => "<unset>", 
                    ARGCOUNT => ARGCOUNT_ONE,
                },
        } );