def request_params(additional_params)
      client_params.merge(additional_params).select { |_, v| !v.nil? }
    end
def request_params(additional_params)
      client_params.merge(additional_params).select { |_, v| !v.nil? }
    end
Adds client params to additional params. If there is a conflict, the value
 from additional_params is used. It can be called multiple times, because
 request_params(request_params(x)) == request_params(x).

 @param Hash
 @return Hash