how to set a default parameter in python

def my_function(num1,num2=0):		#if num2 is not given, it will default it to zero
  return num1 + num2

print(my_function(1,2))				#prints out 3
print(my_function(4))				#prints out 4 since num2 got defaulted to 0

def your_function(arg,kwarg='default'):
    return arg + kwarg

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

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