def opens
      have_key?
      address = @url_private + "/trade_list/"
      params = {
        "type"   => "open",
      }
      h = post_ssl_with_sign(address, params)
      h.map{|x|
        {
          "success"    => "true",
          "id"         => x["id"],
          "rate"       => BigDecimal.new(x["price"].to_s),
          "amount"     => BigDecimal.new(x["amount_outstanding"].to_s),
          "order_type" => x["type"],
        }
      }
    end
def opens
      have_key?
      address = @url_private + "/trade_list/"
      params = {
        "type"   => "open",
      }
      h = post_ssl_with_sign(address, params)
      h.map{|x|
        {
          "success"    => "true",
          "id"         => x["id"],
          "rate"       => BigDecimal.new(x["price"].to_s),
          "amount"     => BigDecimal.new(x["amount_outstanding"].to_s),
          "order_type" => x["type"],
        }
      }
    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"
   ltimestamp: [int] Local Timestamp