def request(operation, version = nil, params = {})
      response = open(request_url(operation, version, params), @http_opts) do |f|
        @raw_response = f.read
        JSON.parse(@raw_response)
      end
      unless response['Header']['Status'] == 'Success'
        raise ApiError.new(response['Header']['Status'], response['Header']['StatusMsg']) 
      end
      extract_result(response, operation)
    end
def request(operation, version = nil, params = {})
      response = open(request_url(operation, version, params), @http_opts) do |f|
        @raw_response = f.read
        JSON.parse(@raw_response)
      end
      unless response['Header']['Status'] == 'Success'
        raise ApiError.new(response['Header']['Status'], response['Header']['StatusMsg']) 
      end
      extract_result(response, operation)
    end
リクエストを実行して結果を返す.
 結果はJSONをパーズしたHash.
 リクエストに失敗したら例外をスローする.