main.py

import random

hobbies = ['a', 'b', 'c']
hobbies_wieghts = [70, 20, 10]

def choice_hobby():
    # list enumerate here wraps the arrary in a list so choices returns the indexes
    c = random.choices(list(enumerate(hobbies)), weights=hobbies_wieghts, k=1)
    # For the first item in the list get the first item in the inner list
    arrary_index = c[0][0]
    # For the first item in the list get the second item in the inner list
    array_value = c[0][1]
    # Set the wieght for this item to 0 so it is never choosen again
    hobbies_wieghts[arrary_index] = 0
    # Return the value
    return array_value

for i in range(len(hobbies)):
    print(choice_hobby())