ros2 commandline service call

What's the correct syntax for performing a service call from the command line in ROS2 ? Consider the following service, defined in `example_interfaces` package AddTwoInts.srv int a int b --- int c Assuming that the server is called `"add_two_ints"` I managed to pass one argument to the service call in the following way $ ros2 service call /add_two_ints example_interfaces/AddTwoInts "a: '1'" requester: making request: example_interfaces.srv.AddTwoInts_Request(a=1, b=0) How to pass also the second argument ? These are not working $ ros2 service call /add_two_ints example_interfaces/AddTwoInts "a: '1'b:'2'" $ ros2 service call /add_two_ints example_interfaces/AddTwoInts "a: '1' b:'2'" $ ros2 service call /add_two_ints example_interfaces/AddTwoInts "a: '1', b:'2'" $ ros2 service call /add_two_ints example_interfaces/AddTwoInts "a:'1'" "b:'2'" $ ros2 service call /add_two_ints example_interfaces/AddTwoInts "a:'1'", "b:'2'"