code: def edges(inputtiles, parsenames):
      
      try:
          inputtiles = click.open_file(inputtiles).readlines()
      except IOError:
          inputtiles = [inputtiles]
  
      # parse the input stream into an array
      tiles = edge_finder.findedges(inputtiles, parsenames)
  
      for t in tiles:
          click.echo(t.tolist())
docs: For a stream of [<x>, <y>, <z>] tiles, return only those tiles that are on the edge.