code works in idle but still says wrong

# 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(thouseteach):
    staff=0
    for key in thouseteach.keys():
        staff +=1
    return int(staff)
def num_courses(thouseteach):
    course = 0
    for value in thouseteach.values():
        for item in value:
            course += 1              
    return courses
def courses(thouseteach):
    course_titles =[]
    for value in thouseteach.values():
        for item in value:
            if item not in course_titles:
                course_titles.append(item)
            else:
                continue
    return course_titles