# Create a function, called student$\_$id$\_$numbers, that takes a list of student names

# and generates an automatic student id number. The function must be able to handle

# collisions using dictionaries. A collision will happen when students have the same

# last name. The function must return the dictionary or dictionaries containing the

# students and their student id numbers.

# Note: using defaultdict might be helpful but not required. Having some good music

# while you code this might be helpful but also not required.

# You will also need to write a second function, called retrieve student$\_$number that

# will take a student's name and will return their student id number. This function

# will need to handle misspelled names. Use 'defaultdict' but do not import from any modules