package My::Class::SubClass;
require My::Class::Base;
@ISA= qw( My::Class::Base );

package My::Class::SubClass::_code;
# Import common non-methods:
My::Class::Base::_code->import( qw( _utilSub _timestamp ) );

# Export below methods to My::Class::SubClass:
for(  grep !/^_/, keys %{ __PACKAGE__ . "::" }  ) {
    *{"My::Class::SubClass::".$_}= \&$_
        if  defined &$_;
}

use strict;

sub new {
    my $us= shift @_;
    ...
    $us->someBaseMethod( @works );
    _utilSub( _timestamp() );
    ...
}

##</code><code>##

package My::Class::Base;
use vars qw( $VERSION );
$VERSION= 1.001_002;

package My::Class::Base::_code;
use vars qw( @EXPORT_OK );
BEGIN {
    require Exporter;
    *import= \&Exporter::import;
    @EXPORT_OK= qw( _utilSub _timestamp );
}

use strict;

sub _timestamp {
    # non-method code
}

# Method version:
*My::Class::Base::_timestamp= sub {
    shift @_;
    return _timestamp();
}