In python 3 , code the following exercise:

Define a function, which inputs student score, and returns student's grades according to the following criterion:

Score	Grade
Less than 40	F
40 to less than 50	D
50 to less than 60	C
60 to less than 70	B
70 to less than 80	A
Greater than 80	A+

Define a function, which inputs student score, and returns student's grades according to the following criterion