package Foo;
sub bar { print join( ',', @_ ) . "\n"; }

package Baz;
push @ISA => "Foo";

package main;
Foo::bar('arg1');
Foo->bar('arg1');
Baz->bar('arg1');
Bar::bar('arg1');

__END__
arg1
Foo,arg1
Baz,arg1
Undefined subroutine &Bar::bar called at - line 9.