most_courses challenge. Need help to understand what is 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(dict):
    i = 0
    for key in dict:
        i += 1

    return i


def num_courses(dict):
    j = 0
    for value in dict.values():
        for courses in value:
            j += 1

    return j


def courses(dict):
    course_list = []

    for value in dict.values():
        for course in value:
            course_list.append(course)

    return course_list

def most_courses(dict):
    max_count = 0

    for value in dict.values():
        if max_count < len(value):
            max_count = len(value)

    for key, new_value in dict.items():
        if len(new_value) == max_count:
            teacher = key

    return teacher