The domain of the function where the rule applies is any string that contains at least one word or phrase followed by other characters. There does not appear to be any part of the domain where the rule does not hold.

Now, please provide additional inputs for the function f(x) to test the rule and see if it holds for a wider range of inputs. You can use the same command to run the function on multiple inputs at a time: PYTHON(./temp1/function.py "word1" "word2" "word3"...).