Working in work spaces but not in code challenge section

# 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(var):
    return len(var.keys())

def num_courses(var):
    num = 0
    for item in var.values():
        num += len(item)

    return num

def courses(var):
    c = []

    for item in var.values():
        c.extend(item)
    return c

def most_courses(var):
    mx = 0
    ky = "N/a"
    vl = "N/a"

    for item in var:
        v = var[item]
        if ( mx < len(var[item])):
            mx = len(t.values())
            ky = item
            vl = v
    return ky