The first input argument of function index() in Problem 6.27 is supposed to be the name of a text file. If the file cannot be found by the interpreter or if it cannot be read as a text file, an exception will be raised. Reimplement function index() so that the message shown here is printed instead:

 

Problem 6.27

At the end of this and other textbooks, there usually is an index that lists the pages where a certain word appears. In this problem, you will create an index for a text but, instead of page number, you will use the line numbers. You will implement function index() that takes as input the name of a text file and a list of words. For every word in the list, your function will find the lines in the text file where the word occurs and print the corresponding line numbers (where the numbering starts at 1). You should open and read the file only once.