code: def union(inputtiles, parsenames):
      
      try:
          inputtiles = click.open_file(inputtiles).readlines()
      except IOError:
          inputtiles = [inputtiles]
      unioned = uniontiles.union(inputtiles, parsenames)
      for u in unioned:
          click.echo(json.dumps(u))
docs: Returns the unioned shape of a steeam of [<x>, <y>, <z>] tiles in GeoJSON.