def delete_param(key)
      code, message, value = @server.call("deleteParam", @caller_id, key)
      case code
      when 1
        return true
      else
        return false
      end
    end
def delete_param(key)
      code, message, value = @server.call("deleteParam", @caller_id, key)
      case code
      when 1
        return true
      else
        return false
      end
    end
delete parameter 'key'
 @param [String] key key for remove
 @return [Boolean] return true if success, false if it is not exist