Select Code to Download

{
    my $warning;
...
    Module::do_something($param, $param1);
    like ($warning, qr/ignoring/, 'param 1 isn't an href, ignored');
}

sub blah {
    my %params = @_;
    ...
}

my $farm = blah(moo => $href, meow => "Phoebe's smelly cat");

sub valid_params {
    my %valid = (
...
        die "param 'moo' must be a hash reference";
    }
}

sub yell {
    my %p = @_;
    _validate_params(%p);
    ...
}