Package == 
=head1 NAME
CGI::Session::ErrorHandler - error handling routines for CGI::Session
=head1 SYNOPSIS
    require CGI::Session::ErrorHandler
    @ISA = qw( CGI::Session::ErrorHandler );
    sub some_method {
        my $self = shift;
        unless (  $some_condition ) {
            return $self->set_error("some_method(): \$some_condition isn't met");
        }
    }
=head1 DESCRIPTION
CGI::Session::ErrorHandler provides set_error() and errstr() methods for setting and accessing error messages from within CGI::Session's components. This method should be used by driver developers for providing CGI::Session-standard error handling routines for their code
=head2 METHODS
=over 4
=item set_error($message)
Implicitly defines $pkg_name::errstr and sets its value to $message. Return value is B
 undef.