code: def alien_filter(packages, sizes):
      
      cache, npkg, nsize = [], [], []
      for p, s in zip(packages, sizes):
          name = split_package(p)[0]
          if name not in cache:
              cache.append(name)
              npkg.append(p)
              nsize.append(s)
      return npkg, nsize
docs: This filter avoid list double packages from
      alien repository