Why is this producing the wrong result?

# 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(my_dict):
    num_of_teachers = 0

    for key in my_dict:
        num_of_teachers += 1
    return num_of_teachers
#End of num_teachers

def num_courses(my_dict):
    num_of_courses = 0

    for value in my_dict.values():
        for item in value:
            num_of_courses += 1
    return num_of_courses


def courses(my_dict):
    course_list = []

    for value in my_dict.values():
        for item in value:
            course_list.append(item)
    return course_list

def most_courses(my_dict):
    answer = ""
    max_val = 0
    dict_items = None
    teacher = ""
    i = 0

    for key in my_dict.keys():
        for item in my_dict.values():
            dict_items = item

            for value in dict_items:
                i += 1

        if i > max_val:
            max_val = i
            teacher = key
        elif i == max_val:
            teacher = teacher + "&" + key       

    return teacher


def stats(my_dict):
    answer = []
    stat = []
    course_cnt = 0

    for key in my_dict.keys():
        for course in my_dict.values():
            course_cnt += 1

        stat = [key, course_cnt]
        course_cnt = 0
        answer.extend(stat)

    return answer