Option for slicker to make a method private

I often find myself doing something like
```
slicker foo_package.bar_module.baz_long_helper_name foo_package.bar_module._baz_long_helper_name
```
which is a pain to type out, even more so when you want to do 10 of them.  We could have a shortcut for this!  Ideally it would even allow me to do multiple at once.