Why aren't the values from the for loop appending to the array?

I'm trying to append values from a for loop into a numpy array. While the values are correct, the array only returns none values. The values entered are from another numpy array.

import numpy as np
import matplotlib.pyplot as plt

j=np.array([14,15,16,16,16,22,22,24,24,25,25,25,25,25])
u=np.unique(j)


def P(age):
    sum=0
    for i in range(14):
        if j[i]==age:
            sum=sum+1
        else:
            sum=sum
    print(sum/14)
    
p = []
for i in range(6):
    p.append(P(u[i]))
p=np.array(p)
print(p)
print(type(p))

Output:

0.07142857142857142
0.07142857142857142
0.21428571428571427
0.14285714285714285
0.14285714285714285
0.35714285714285715
[None None None None None None]
<class 'numpy.ndarray'>

Function "P" doesn't have a return function, hence equaling None each time.

def P(age):
    sum=0
    for i in range(14):
        if j[i]==age:
            sum=sum+1
        else:
            sum=sum
    print(sum/14)
    return sum/14

Shown here ^, you can return the sum.

Because your function P() has no return statement, i.e. it returns None.

You probably want to change the last statement of this function definition, i.e. the statement

print(sum/14)

to

return sum/14

(or append this return statement after your print(sum/14).)