Pipe-sign every time I execute

Hi All, I have a simple function (nothing fancy) whose header definition is as below:

procedure( my_func( cellName netName @optional (arg1 "abc") (arg2 "def")  )

    let(  (inport...etc. ec.

I have two questions:

(a) Everytime I execute the function, I get a "|"<process_name> at the start and end, as shown below:

my_func( "mycell" "mynet")

|my_func("mycell" "mynet")

..................... 

|my_func --> t

t 

(2) How do I pass arg2 without having to pass arg1? Something like my_func( "mycell" "mynet" ?arg2 "myarg")