1. ''' '''the comment in the middle will be shown in your code while ranning

2. a=b
c=a%b
or we can simplify them into:a, c=b, a%b

3. while we wanna test your code in another file, we need to (1) import + file_name  (2) file_name.function_name( your input)

or we can do (1) from file_name import function_name  (2) function_name( your input )

4. testmod() will import what inside ''' ''' as input and see is the output is same what is inside ''' ''' as well, like final exam

5. when we are 调用function, we can add a * in the front of the function when the output appears with pairs, as so we can remove the pears
def f():
　　return (2,4,5)
def f(a,b,c):
　　return 2*a+b+c
　　return g(*f())

6. (0,0)*2=(0,0,0,0)
((0,0))*2=((0,0),(0,0))

7. format: for example, we got x=90

f'{x: 8b}'  means we will use empty to make it occupy 8 spaces in total

f'{5:08b}' means we will use 0 to do that

8. x%10 can get the right most number
x //10%10 can get the second one from right side
x//100%10 the third one