def opens
      have_key?
      address = @url_private + "/me/getchildorders"
      query = {
        "child_order_state" => "ACTIVE",
      }
      address += "?" + query.to_a.map{|x|"#{x[0]}=#{x[1]}" }.join("&")
      body = {
        "product_code" => @product_code,
      }
      a = get_ssl_with_sign(address, body)
      a.map{|x|
        {
          "success"    => "true",
          "id"         => x["child_order_acceptance_id"],
          "rate"       => BigDecimal.new(x["average_price"].to_s),
          "amount"     => BigDecimal.new(x["size"].to_s),
          "order_type" => x["side"].downcase,
        }
      }
    end
def opens
      have_key?
      address = @url_private + "/me/getchildorders"
      query = {
        "child_order_state" => "ACTIVE",
      }
      address += "?" + query.to_a.map{|x|"#{x[0]}=#{x[1]}" }.join("&")
      body = {
        "product_code" => @product_code,
      }
      a = get_ssl_with_sign(address, body)
      a.map{|x|
        {
          "success"    => "true",
          "id"         => x["child_order_acceptance_id"],
          "rate"       => BigDecimal.new(x["average_price"].to_s),
          "amount"     => BigDecimal.new(x["size"].to_s),
          "order_type" => x["side"].downcase,
        }
      }
    end
Get open orders.
 @abstract
 @return [Array] open_orders_array
   @return [hash] history_order_hash
     success: [bool]
     id: [String] order id in the market
     rate: [BigDecimal]
     amount: [BigDecimal]
     order_type: [String] "sell" or "buy"
     order_status: [String] "active", "completed" or "canceled"
   ltimestamp: [int] Local Timestamp