where to set default values in python code example

Example 1: python default arguments

def my_function(name, age = 20):
  print(name + " is " + str(age) + " years old"

my_function("Mitro") # Mitro is 20 years old
my_function("Mitro", 26) #Mitro is 26 years old

Example 2: python function parameters default value

def F(a, b=None):
    if b is None:
        b = []
    b.append(a)
    return b