Renamed level parameter to make it clear that it's 'private.'
Renamed level parameter to make it clear that it's 'private.'

The level parameter is just used for logging since the function is called
recursively, so in general it shouldn't be called directly with anything but
the default value (0). Prepending the underscore should better communicate
this per Python naming conventions.

tylerbutler/engineer,tylerbutler/engineer,tylerbutler/engineer