Select Code to Download

        if ( ref( $value ) ) {                   # <- that's a ref!
            # We have multiple values for this key
...
            $value = uri_escape( $value, $cgi_chars );
            $query_string .= "$key=$value&";
        }

        if ( ! ref( $value ) ) {
            $value = uri_escape( $value, $cgi_chars );
...
                $query_string .= "$key=$array_value&";
            }
        }

    if(  UNIVERSAL::isa( $r, "ARRAY" )  ) {
        # access @$r here
    } elsif(  UNIVERSAL::isa( $r, "HASH" )  ) {
        # access %$r here

    if(  ref($r)  &&  "$r" =~ /(^|=)HASH/  ) {

sub method {
    my $self= shift;
    die "Invalid object" unless ref($self) eq "My::Package";

    die "Invalid object" unless UNIVERSAL::isa( $self, __PACKAGE__ );
# or
    die "Invalid object" unless eval { $self->isa(__PACKAGE__) };

if(  ref($r)  &&  "$r" =~ /=/  )