def install(h, pip, groups, save, save_dev, packages):
    """Install a pip or bower package."""
    if groups:
        groups = [text_type.strip(group) for group in groups.split(",")]
    else:
        groups = h.requirements.keys()

    if not packages:
        for group in groups:
            if group not in h.requirements:
                warning("{} not in requirements".format(group))
                continue
            install = (h.install_bower if group.startswith("bower")
                       else h.install_pip)
            for requirement in h.requirements[group]:
                install(str(requirement), save=False, save_dev=False)
    if pip:
        for package in packages:
            h.install_pip(package, save=save, save_dev=save_dev)
    else:
        for package in packages:
            h.install_bower(package, save=save, save_dev=save_dev)
def setSaSS(self, lenp2, lenp3, lenp1):
        self.lenp2 = lenp2
        self.lenp3 = lenp3
        self.lenp1 = lenp1
        if(self.lenp1 > (self.lenp2 + self.lenp3)):
        #<CAB 夾角為 180 度, 三點共線且 A 介於 BC 之間
            ret = math.pi
        else :
            # <CAB 夾角為 0, 三點共線且 A 不在 BC 之間
            if((self.lenp1 < (self.lenp2 - self.lenp3)) or (self.lenp1 < (self.lenp3 - self.lenp2))):
                ret = 0.0
            else :
            # 透過餘絃定理求出夾角 <CAB 
                ret = math.acos(((self.lenp2 * self.lenp2 + self.lenp3 * self.lenp3) - self.lenp1 * self.lenp1) / (2 * self.lenp2 * self.lenp3))
        return ret