my $passwd = Text::Hidden->new( "12345",
      auto_unhide => [
          "Some::Class::Authentication",       # anywhere in Authentication package
          "Some::OtherClass::authenticate()",  # anywhere in authenticate method
          "Some::OtherClass::foo(43)",         # line 43 in method foo (FRAGILE!)
      ],

      # similar, but search call stack (not just immediate caller) for a match
      auto_unhide_recursive => [ ... ],
  );