Help with python

Letter Grade Given an integer score, we determine the letter grade and return the string. Possible return values are "A+", "A", "A-", "B+", "B", etc. It will exactly match our own semester's grading scale, so look at the grading scale in our syllabus if you need a refresher. def letter_grade (score): Given a non-negative integer score, determine what the actual grade should be based on our semester grading scale: return a string directly representing that grade. score will be a non-negative integer. Examples letter-grade(95) rightarrow "A" letter-grade(89) rightarrow "B+" letter-grade(61) rightarrow "D" This time, our function to implement accepts three arguments. But we want to only find the sum of the two largest values of the three. def sum2biggest(a, b, c): Given three integer arguments, determine what the two biggest ones are, add them together, and return that result. all three parameters a, b, and c will be integers: note that they can be positive, zero, or o negative! Examples sum2biggest(5, 3, 4) rightarrow 9 sum2biggest(-5, -3, -1) rightarrow -4 sum2biggest(6, 4, 6) rightarrow 12 sum2biggest(0, 0, 0) rightarrow 0