my $res = $Doc->find (
sub {
    if ($_[1]->class eq 'PPI::Statement')
    {
        # find all PPI::Token::Words within the statement that have
        # literal equal to Mod::func
        # non-zero return means it found something
        $_[1]->find(sub {
            $_[1]->isa('PPI::Token::Word') and
                $_[1]->literal eq 'Mod::func';
        })
        }
    else {return 0;}
}
);