Can anyone give me a hint on this challenge?

# The dictionary will look something like:
# {'Andrew Chalkley': ['jQuery Basics', 'Node.js Basics'],
#  'Kenneth Love': ['Python Basics', 'Python Collections']}
#
# Each key will be a Teacher and the value will be a list of courses.
#
# Your code goes below here.
def num_teachers(teachers):
    count = 0
    for teacher in teachers:
        count += 1 
    return count

def num_courses(argument):
    count = 0
    for val in argument.values():
        count = count + len(val)
    return count

def courses(argument):
    courses = []
    for val in argument.values():
        courses += val
    return courses