Error when passing multiple --cache args

[coderholic]

I get an error when passing in multiple --cache arguments:

$ ./elastic-mapreduce 
  --create
  --cache <file1>
  --cache <file2>
  ...

Error: Repeating --cache CACHE_FILE is not allowed, previous value was "<file1>"

EMR definitely supports multiple cache files though, and line 781 of commands.rb seems to support it too:

      stream_options = []
      for ca in get_field(:cache, []) do
        stream_options << "-cacheFile" << ca
      end

Is this a bug, or is there another way in which I should pass in multiple cache files? (I already tried a single --cache <file1>,<file2>,<file3> but my job eventually failed saying that it didn't have a valid cache URL)