code: def hit(self, rect):
          
  
          # Find the hits at the current level.
          hits = {tuple(self.items[i]) for i in rect.collidelistall(self.items)}
  
          # Recursively check the lower quadrants.
          if self.nw and rect.left <= self.cx and rect.top <= self.cy:
              hits |= self.nw.hit(rect)
          if self.sw and rect.left <= self.cx and rect.bottom >= self.cy:
              hits |= self.sw.hit(rect)
          if self.ne and rect.right >= self.cx and rect.top <= self.cy:
              hits |= self.ne.hit(rect)
          if self.se and rect.right >= self.cx and rect.bottom >= self.cy:
              hits |= self.se.hit(rect)
  
          return hits
docs: Returns the items that overlap a bounding rectangle.
  
          Returns the set of all items in the quad-tree that overlap with a
          bounding rectangle.
  
          @param rect:
              The bounding rectangle being tested against the quad-tree. This
              must possess left, top, right and bottom attributes.