Create final-3-regress.py

# Regression Testing
# ------------------
# The goal of this problem is for you to write a regression tester
# for the Queue class.
# 
# Begin by finding and fixing all of the bugs in the Queue class. Next,
# define the function regression_test to take in a list of enqueue inputs
# and dequeue indicators (the returned list of the previous problem) and
# repeat those method calls using the fixed Queue.
# 
# That is, after fixing the Queue class, create a new Queue instance,
# and call the method corresponding to the indicator in the list
# for each item in the list:
# 
# Call the enqueue function whenever you come across an integer, using that
#     integer as the argument.
# Call the dequeue function whenever you come across the 'dq' indicator.