Dict_set.py

This does print the desired result, but this is a really roundabout way to create and print a set. 

`'seperator'.join(iterable)` returns a string that is a concatenation of all the strings in an iterable with the separator between them. In this case, `word` is the iterable; it contains one string, so the separator is not included in the returned string

    ','.join(word) == 'Python'
    >>> True

 `str.replace('old', 'new')` returns a copy of the string it's called on with all occurrences of the old character(s) replaced by the new. Since `','.join(word)` returns a string without a comma, 

    ','.join(word) == ','.join(word).replace(',', '')
    >>> True

Ultimately, this code is calling `set('Python')`, which produces the desired set because `set()` will construct a set out of an iterable such as a string. The direct way to produce this set is to condense lines 68-70 into:

    set('Python')