def cancel(id)
      have_key?
      address = @url_private + "/me/cancelchildorder"
      body = {
        "product_code"              => @product_code,
        "child_order_acceptance_id" => id
      }
      h = post_ssl_with_sign(address, body)
      {
        "success" => h
      }
    end
def cancel(id)
      have_key?
      address = @url_private + "/me/cancelchildorder"
      body = {
        "product_code"              => @product_code,
        "child_order_acceptance_id" => id
      }
      h = post_ssl_with_sign(address, body)
      {
        "success" => h
      }
    end
Cancel an open order
 @abstract
 @param [int or string] order id
 @return [hash]
   success: [bool] status