Im stuck at challenge 3 it says task 1 is no longer passing

# 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(teachers): 
  maxNum = 0 
  name = '' 

  for teacher in teachers:
    if len(teachers[teacher])>maxNum:
      name = teacher

  return name    

def num_teachers(teachers):
  return len(teachers.keys())

def stats(teachers):

  my_list=[]

  for teacher in teachers:

    a_list = [teacher , len(teachers[teacher])]
    my_list = my_list.append(a_list)

  return my_list