class ResearchArea(object):
    NAME = None
    PREREQUISITES = ()

    def __init__(self):
        self.points = 0

    def spend_points(self, points):
        self.points += points


class Tesla(ResearchArea):
    NAME = "Tesla"


class Robotics(ResearchArea):
    NAME = "Robotics"


class Rocketry(ResearchArea):
    NAME = "Rocketry"


class BioGenetics(ResearchArea):
    NAME = "Biogenetics"


class Space(ResearchArea):
    NAME = "SPAAAAAACE!"
    PREREQUISITES = (
        (Robotics, 1),
        (Rocketry, 2),
        )