Add method words() to class Textfile from Problem 8.28. It takes no input and returns a list, without duplicates, of words in the file.

 

Problem 8.28

Develop a class Text file that provides methods to analyze a text file. The class Text file will support a constructor that takes as input a file name (as a string) and instantiates a Text file object associated with the corresponding text file. The Text file class should support methods nchars(), nwords(), and nlines() that return the number of characters, words, and lines, respectively, in the associated text file. The class should also support methods read() and read lines() that return the content of the text file as a string or as a list of lines, respectively, just as we would expect for file objects. Finally, the class should support method grep () that takes a target string as input and searches for lines in the text file that contain the target string. The method returns the lines in the file containing the target string; in addition, the method should print the line number, where line numbering starts with 0.