def add(self, elem, replace=False):
        """Add a requirement.

        :param elem: a string or :class:`Requirement` instance.
        :param replace: if `True`, packages in the set with the same name will
            be removed first.
        """
        if isinstance(elem, text_type):
            elem = Requirement.coerce(elem)
        if replace and elem in self:
            self.remove(elem)
        super(Requirements, self).add(elem)
def __init__(self, container):
		self.x = container.x+randint(1, floor(container.w/3))
		self.y = container.y+randint(1, floor(container.h/3))
		self.w = container.w-(self.x-container.x)
		self.h = container.h-(self.y-container.y)
		self.w -= randint(0,floor(self.w/3))
		self.h -= randint(0,floor(self.w/3))
		self.environment = int(min(4,10*(container.distance_from_center/MAP_WIDTH)+random()*2-1))
		roll = random()*0.9+(2*container.distance_from_center/MAP_WIDTH)*0.1
		self.biome = next(n for n,b in enumerate(self.biomes_CDF) if roll<b)