please help

I don't know what your exact question is, but I assume that you're trying to add song4.

I would personally do it like this:

songs = {'song1': 'Python Two-step', 'song2': 'Ruby Rhumba', 'song3': 'My PDF Files'} 
# Now, I assume you wish to add song4 which you can do in multiple ways.
songs['song4'] = 'Treehouse Hula'
# You can also add a song like this:
song4 = { 'song4' = 'Treehouse Hula' }
songs.update(song4) # I personally find it easier to do the first method. 

Blessing you are essentially correct. The automated grader was looking for EXACT case

You mistakenly did not put a capital S on "Python Two-step" where it should have been "Python Two-Step"

Under Python3 (workspaces) your code produces this set ordering-- in theory, a set has no order.

songs = {'song1','song2','song3'}
songs.add('Treehouse Hula')
songs.update({'Python Two-step'},{'Ruby Rhumba'},{'My PDF Files'})
print(songs)

$ python blessing.py
{'song2', 'Treehouse Hula', 'song3', 'song1', 'Ruby Rhumba', 'Python Two-step', 'My PDF Files'}

I wrote the code how I think the teacher wanted it (I cut-and-pasted), and it passed the challenge. But, it produces an equivalent set with a different "ordering".

songs = {'song1', 'song2', 'song3'} # instantiation of songs set object
songs.add('Treehouse Hula') # a simple addition of a string object
songs.update({"Python Two-Step", "Ruby Rhumba"}) # update songs with another 2 item set
songs.update({"My PDF Files"}) # update songs with a 1 item set

Under Python3 (workspaces) produces this ordering, but it is equivalent to Blessing's set.

$ python jeff.py
{'song1', 'Python Two-Step', 'My PDF Files', 'Ruby Rhumba', 'Treehouse Hula', 'song3', 'song2'}

Don't worry about it, enjoy Python! *Sometimes the computer tests aren't smart enough to recognize a student got the right answer or something really close to it! *