Python 3, my professor supplied me with a sample file

1 Implement a function longest Word () that takes one parameter which is a string representing the name of a text file. The function should return the length of the largest word in the file. The punctuation in the file should be removed (see str.maketrans) prior to determining the average length of a word in the file. For the purposes of this question the valid punctuation symbols are commas (,), periods (.), exclamation marks (!), question marks (?), semicolons (:), and colons (:). If the file is empty, the function should return 0