gistfile1.txt

>>> def bad_idea(value, arg=[]):
...     arg.append(value)
...     print(arg)
...     if value % 2 == 0:
...         return True
...     else: 
...         return False
... 
>>> bad_idea(1)
[1]
False
>>> bad_idea(3)
[1, 3]
False
>>> bad_idea(4)
[1, 3, 4]
True
>>> bad_idea(4, [4])
[4, 4]
True
>>> bad_idea(4)
[1, 3, 4, 4]
True
>>> bad_idea(5)
[1, 3, 4, 4, 5]
False
>>> 

scratch.py

def bad_idea(value, arg=[]):
    arg.append(value)
    print(arg)
    
    if value % 2 == 0:
        return True
    else: 
        return False