def coerce(cls, string):
        """Create a :class:`Requirement` object from a given package spec."""
        match = re.match(cls.spec_regex, string)
        if not match:
            raise InvalidRequirementSpecError("could not parse requirement")
        package = match.group(1)
        if all(match.group(2, 3)):
            version = "".join(match.group(2, 3))
        else:
            version = None
        return cls(package, version)
def __init__(self, x, y, w, h):
		self.x = x
		self.y = y
		self.w = w
		self.h = h
		self.center = (self.x+int(self.w/2),self.y+int(self.h/2))
		self.distance_from_center = sqrt((self.center[0]-MAP_WIDTH/2)**2 + (self.center[1]-MAP_HEIGHT/2)**2)