default paramiter in [ython code example

Example 1: default values python

class Test:
    def __init__(self, val, num = 0):
        self.val = val
        self.num = num

# you can write this:

t = Test(1)
print(t.num) # prints 0

# OR this

t = Test(1, 2)
print(t.num) # prints 2

Example 2: python function parameters default value

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