问Elixir编译错误:具有多个子句和默认值的定义需要标头

EN

  def stream(query, opts \\ []) do
    initial_key = Keyword.get(opts, :initial_key, 0)
    key_name = Keyword.get(opts, :key_name, :id)
    chunk_size = Keyword.get(opts, :chunk_size, 500)

    Stream.resource(fn -> {query, initial_key} end,
      fn {query, last_seen_key} ->
        results = query
          |> Ecto.Query.where([r], field(r, ^key_name) > ^last_seen_key)
          |> Ecto.Query.limit(^chunk_size) 
          |> __ENV__.module.all

        case List.last(results) do
          %{^key_name => last_key} ->
            {results, {query, last_key}}
          nil ->
            {:halt, {query, last_seen_key}}
        end
      end,
      fn _ -> [] end)
  end

== Compilation error on file lib/peanutbutter/repo.ex ==
** (CompileError) lib/peanutbutter/repo.ex:3: definitions with multiple clauses and default values require a header. Instead of:

    def foo(:first_clause, b \\ :default) do ... end
    def foo(:second_clause, b) do ... end

one should write:

    def foo(a, b \\ :default)
    def foo(:first_clause, b) do ... end
    def foo(:second_clause, b) do ... end

def stream/2 has multiple clauses and defines defaults in one or more clauses
    lib/peanutbutter/repo.ex:3: (module)
    (stdlib) erl_eval.erl:670: :erl_eval.do_apply/6
    (elixir) lib/kernel/parallel_compiler.ex:117: anonymous fn/4 in Kernel.ParallelCompiler.spawn_compilers/1