code: def _group_coords(rs):
      
      max_intron_size = 1e5
      coords = []
      for r in rs:
          coords.append(r.start)
          coords.append(r.end)
      coord_groups = []
      cur_group = []
      for coord in sorted(coords):
          if not cur_group or coord - cur_group[-1] < max_intron_size:
              cur_group.append(coord)
          else:
              coord_groups.append(cur_group)
              cur_group = [coord]
      if cur_group:
          coord_groups.append(cur_group)
      return coord_groups
docs: Organize coordinate regions into groups for each transcript.
  
      Avoids collapsing very large introns or repetitive genes spread across
      the chromosome by limiting the intron size to 100kb for creating a single transcript