12:34:56.78 LOG:
12:34:56.78 ............ <f-string value> = '1'
12:34:56.78 ........ f"b {x} c" = 'b 1 c'
12:34:56.78 .... "a" + f"b {x} c" = 'ab 1 c'
12:34:56.78 LOG:
12:34:56.78 ............ <f-string value 1> = '1'
12:34:56.78 ............ <f-string value 2> = '2'
12:34:56.78 ........ f"b {x} {x * 2} c" = 'b 1 2 c'
12:34:56.78 .... "a" + f"b {x} {x * 2} c" = 'ab 1 2 c'