def set_param(key, value)
      code, message, value = @server.call("setParam", @caller_id, key, value)
      case code
      when 1
        return true
      when -1
        raise message
      else
        return false
      end
    end
def set_param(key, value)
      code, message, value = @server.call("setParam", @caller_id, key, value)
      case code
      when 1
        return true
      when -1
        raise message
      else
        return false
      end
    end
set parameter for 'key'
 @param [String] key key of parameter
 @param [String, Integer, Float, Boolean] value value of parameter
 @return [Boolean] true if succeed
 @raise