package Log;

sub new { 
  my ($class) = shift;
  bless {}, $class;
}

sub write {
  print "write old\n";
}

sub open {
  print  "open old\n";
}

sub close {
  print "close old\n";
}
1;

package NewLog;

sub import {
  for my $sub (qw(new write open)) {
    no strict 'refs';
    *{'Log::'.$sub} = *{'NewLog::'.$sub};
  }
}

sub new { 
  my ($class) = shift;
  bless {}, $class;
}

sub write {
  print "write new\n";
}

sub open {
  print  "open new\n";
}
1;

use Log;
use NewLog;

my $log = new Log;
$log->open;
$log->write;
$log->close;

##</code><code>##

open new
write new
close old