def check_skill(self, entity, skill, modifier=0):
skill_level = self.get_skill_level(entity, skill_tree[skill])
skill_level += modifier
roll = random.roll_dice(3)
success = roll <= skill_level or roll <= 4
critical = roll <= 6 and roll*3 <= skill_level
dos = skill_level - roll
if success and critical:
dos += random.roll_dice()
# Degree of Success on a critical is always at least 1
dos = max(dos, 1)
elif success:
# Degree of Success is always at least 0 for a success
dos = max(dos, 0)
return SkillCheckEvent.Result(success, critical, roll, dos)
