old_contents: import os
  
  from whack.caching import DirectoryCacher, NoCachingStrategy
  import whack.builder
  
  def install(package, install_dir, caching, builder_uris, params):
      if caching.enabled:
          cacher = DirectoryCacher(os.path.expanduser("~/.cache/whack/builds"))
      else:
          cacher = NoCachingStrategy()
              
      builder = whack.builder.Builders(cacher, builder_uris)
      builder.install(package, install_dir, params)
  
  
new_contents: import os
  
  from whack.caching import HttpCacher, DirectoryCacher, NoCachingStrategy
  import whack.builder
  
  def install(package, install_dir, caching, builder_uris, params):
      if not caching.enabled:
          cacher = NoCachingStrategy()
      elif caching.http_cache_url is not None:
          # TODO: add DirectoryCacher in front of HttpCacher
          cacher = HttpCacher(caching.http_cache_url, caching.http_cache_key)
      else:
          cacher = DirectoryCacher(os.path.expanduser("~/.cache/whack/builds"))
              
      builder = whack.builder.Builders(cacher, builder_uris)
      builder.install(package, install_dir, params)
  
  
subject: Implement HTTP caching when CLI option is set