I am getting the error: "Bummer! your returned 5 courses when it should return 18"

# The dictionary will be something like:
# {'Jason Seifer': ['Ruby Foundations', 'Ruby on Rails Forms', 'Technology Foundations'],
#  'Kenneth Love': ['Python Basics', 'Python Collections']}
#
# Often, it's a good idea to hold onto a max_count variable.
# Update it when you find a teacher with more classes than
# the current count. Better hold onto the teacher name somewhere
# too!
#
# Your code goes below here.
def most_classes(teacher_dict):
  big_num = 0
  big_teacher = ''
  for teacher in teacher_dict:
    class_num = len(teacher_dict[teacher])
    if (class_num > big_num):
      big_num = class_num
      big_teacher = teacher
  return big_teacher

def num_teachers(teacher_dict):
  total_teachers = 0
  for key in teacher_dict:
    total_teachers += 1
  return total_teachers

def stats(teacher_dict):
  teacher_list = []
  for key in teacher_dict:
    my_list = []
    my_list.append(key)
    my_list.append(len(teacher_dict[key]))
    teacher_list.append(my_list)
  return teacher_list

def courses(teachers):
    output = []
    for courses in teachers.values():
        output.append(courses)
    return output