def f(a):
    return len(a)
print(f([1,2,3]))
def z(m):
    s=0
    for c in m:
        s=s+c
    return s
print(z([1,2,3]))

  
>>> def f(a):
...     return len(a)
... 
>>> def z(m):
...     s = 0
...     for c in m:
...         s = s + c
...     return s
... 
>>> print(z([1, 2, 3]) / f([1, 2, 3]))
2.0
>>>