code: def add_poly(self, positions, depth=None):
          
          if not (len(positions) >= 3): raise AssertionError("A minimum of three coordinate pairs are required")
  
          if depth is None or depth > self.maxdepth:
              depth = self.maxdepth
  
          ras, decs = np.array(list(zip(*positions)))
          sky = self.radec2sky(ras, decs)
          pix = hp.query_polygon(2**depth, self.sky2vec(sky), inclusive=True, nest=True)
          self.add_pixels(pix, depth)
          self._renorm()
          return
docs: Add a single polygon to this region.
  
          Parameters
          ----------
          positions : [[ra, dec], ...]
              Positions for the vertices of the polygon. The polygon needs to be convex and non-intersecting.
  
          depth : int
              The deepth at which the polygon will be inserted.