def things_near(self, location, radius=None):
"Return all things within radius of location."
if radius is None:
radius = self.perceptible_distance
radius2 = radius * radius
return [(thing, radius2 - distance2(location, thing.location)) for thing in self.things
if distance2(location, thing.location) <= radius2]
def things_near(self, location, radius=None):
"""Return all things within radius of location."""
if radius is None:
radius = self.perceptible_distance
radius2 = radius * radius
return [(thing, radius2 - distance2(location, thing.location)) for thing in self.things
if distance2(location, thing.location) <= radius2]