How to use the pyperformance.benchmarks.bm_deltablue.Strength function in pyperformance

def __init__(self, strength, name):
        super(Strength, self).__init__()
        self.strength = strength
        self.name = name

2: self.__class__.NORMAL,
            3: self.__class__.STRONG_DEFAULT,
            4: self.__class__.PREFERRED,
            # TODO: This looks like a bug in the original code. Shouldn't this be
            #       ``STRONG_PREFERRED? Keeping for porting sake...
            5: self.__class__.REQUIRED,
        }
        return strengths[self.strength]


# This is a terrible pattern IMO, but true to the original JS implementation.
Strength.REQUIRED = Strength(0, "required")
Strength.STRONG_PREFERRED = Strength(1, "strongPreferred")
Strength.PREFERRED = Strength(2, "preferred")
Strength.STRONG_DEFAULT = Strength(3, "strongDefault")
Strength.NORMAL = Strength(4, "normal")
Strength.WEAK_DEFAULT = Strength(5, "weakDefault")
Strength.WEAKEST = Strength(6, "weakest")


class Constraint(object):

    def __init__(self, strength):
        super(Constraint, self).__init__()
        self.strength = strength

    def add_constraint(self):
        global planner
        self.add_to_graph()
        planner.incremental_add(self)

    def satisfy(self, mark):

0: self.__class__.WEAKEST,
            1: self.__class__.WEAK_DEFAULT,
            2: self.__class__.NORMAL,
            3: self.__class__.STRONG_DEFAULT,
            4: self.__class__.PREFERRED,
            # TODO: This looks like a bug in the original code. Shouldn't this be
            #       ``STRONG_PREFERRED? Keeping for porting sake...
            5: self.__class__.REQUIRED,
        }
        return strengths[self.strength]


# This is a terrible pattern IMO, but true to the original JS implementation.
Strength.REQUIRED = Strength(0, "required")
Strength.STRONG_PREFERRED = Strength(1, "strongPreferred")
Strength.PREFERRED = Strength(2, "preferred")
Strength.STRONG_DEFAULT = Strength(3, "strongDefault")
Strength.NORMAL = Strength(4, "normal")
Strength.WEAK_DEFAULT = Strength(5, "weakDefault")
Strength.WEAKEST = Strength(6, "weakest")


class Constraint(object):

    def __init__(self, strength):
        super(Constraint, self).__init__()
        self.strength = strength

    def add_constraint(self):
        global planner
        self.add_to_graph()
        planner.incremental_add(self)

3: self.__class__.STRONG_DEFAULT,
            4: self.__class__.PREFERRED,
            # TODO: This looks like a bug in the original code. Shouldn't this be
            #       ``STRONG_PREFERRED? Keeping for porting sake...
            5: self.__class__.REQUIRED,
        }
        return strengths[self.strength]


# This is a terrible pattern IMO, but true to the original JS implementation.
Strength.REQUIRED = Strength(0, "required")
Strength.STRONG_PREFERRED = Strength(1, "strongPreferred")
Strength.PREFERRED = Strength(2, "preferred")
Strength.STRONG_DEFAULT = Strength(3, "strongDefault")
Strength.NORMAL = Strength(4, "normal")
Strength.WEAK_DEFAULT = Strength(5, "weakDefault")
Strength.WEAKEST = Strength(6, "weakest")


class Constraint(object):

    def __init__(self, strength):
        super(Constraint, self).__init__()
        self.strength = strength

    def add_constraint(self):
        global planner
        self.add_to_graph()
        planner.incremental_add(self)

    def satisfy(self, mark):
        global planner

def recalculate(self):
        ihn = self.input()
        out = self.output()
        out.walk_strength = Strength.weakest_of(
            self.strength, ihn.walk_strength)
        out.stay = ihn.stay

        if out.stay:
            self.execute()

out = constraint.output()
        constraint.mark_unsatisfied()
        constraint.remove_from_graph()
        unsatisfied = self.remove_propagate_from(out)
        strength = Strength.REQUIRED
        # Do-while, the Python way.
        repeat = True

        while repeat:
            for u in unsatisfied:
                if u.strength == strength:
                    self.incremental_add(u)

                strength = strength.next_weaker()

            repeat = strength != Strength.WEAKEST

1: self.__class__.WEAK_DEFAULT,
            2: self.__class__.NORMAL,
            3: self.__class__.STRONG_DEFAULT,
            4: self.__class__.PREFERRED,
            # TODO: This looks like a bug in the original code. Shouldn't this be
            #       ``STRONG_PREFERRED? Keeping for porting sake...
            5: self.__class__.REQUIRED,
        }
        return strengths[self.strength]


# This is a terrible pattern IMO, but true to the original JS implementation.
Strength.REQUIRED = Strength(0, "required")
Strength.STRONG_PREFERRED = Strength(1, "strongPreferred")
Strength.PREFERRED = Strength(2, "preferred")
Strength.STRONG_DEFAULT = Strength(3, "strongDefault")
Strength.NORMAL = Strength(4, "normal")
Strength.WEAK_DEFAULT = Strength(5, "weakDefault")
Strength.WEAKEST = Strength(6, "weakest")


class Constraint(object):

    def __init__(self, strength):
        super(Constraint, self).__init__()
        self.strength = strength

    def add_constraint(self):
        global planner
        self.add_to_graph()
        planner.incremental_add(self)

def choose_method(self, mark):
        if self.v1.mark == mark:
            if self.v2.mark != mark and Strength.stronger(self.strength, self.v2.walk_strength):
                self.direction = Direction.FORWARD
            else:
                self.direction = Direction.BACKWARD

        if self.v2.mark == mark:
            if self.v1.mark != mark and Strength.stronger(self.strength, self.v1.walk_strength):
                self.direction = Direction.BACKWARD
            else:
                self.direction = Direction.NONE

        if Strength.weaker(self.v1.walk_strength, self.v2.walk_strength):
            if Strength.stronger(self.strength, self.v1.walk_strength):
                self.direction = Direction.BACKWARD
            else:
                self.direction = Direction.NONE
        else:
            if Strength.stronger(self.strength, self.v2.walk_strength):
                self.direction = Direction.FORWARD
            else:
                self.direction = Direction.BACKWARD