def ticker
      h = get_ssl(@url_public + "/getticker?product_code=#{@product_code}")
      {
        "ask"        => BigDecimal.new(h["best_ask"].to_s),
        "bid"        => BigDecimal.new(h["best_bid"].to_s),
        "last"       => BigDecimal.new(h["ltp"].to_s),
        # "high" is not supplied.
        # "low" is not supplied.
        "volume"     => BigDecimal.new(h["volume"].to_s),
        "ltimestamp" => Time.now.to_i,
        "timestamp"  => DateTime.parse(h["timestamp"]).to_time.to_i,
      }
    end
def ticker
      h = get_ssl(@url_public + "/getticker?product_code=#{@product_code}")
      {
        "ask"        => BigDecimal.new(h["best_ask"].to_s),
        "bid"        => BigDecimal.new(h["best_bid"].to_s),
        "last"       => BigDecimal.new(h["ltp"].to_s),
        # "high" is not supplied.
        # "low" is not supplied.
        "volume"     => BigDecimal.new(h["volume"].to_s),
        "ltimestamp" => Time.now.to_i,
        "timestamp"  => DateTime.parse(h["timestamp"]).to_time.to_i,
      }
    end
API for public information

 Get ticker information.
 @return [hash] ticker
   ask: [BigDecimal] 最良売気配値
   bid: [BigDecimal] 最良買気配値
   last: [BigDecimal] 最近値(?用語要チェック), last price
   high: [BigDecimal] 高値
   low: [BigDecimal] 安値
   volume: [BigDecimal] 取引量
   ltimestamp: [int] ローカルタイムスタンプ
   timestamp: [int] タイムスタンプ