Bowling scoring kata
It doesn't look like too many selfs to me.




class Game:

  _rolls = [0] * 21
  _current_roll = 0

  ...



3 things right off the bat:


What's with the blank line between class Game: and _rolls = [0] * 21?
You are using 2 spaces to indent. Use 4 spaces.
Shouldn't this be in the __init__ function?:


_rolls = [0] * 21
_current_roll = 0




So it would look like:

class Game:
    def __init__(self):
        self._rolls = [0] * 21
        self._current_roll = 0

    def roll(self, pins):
        self._rolls[self._current_roll] = pins
        self._current_roll += 1

    ...