def get_average_grade(scores):

  # Validate that the list is not empty to     
  #avoid division by zero error
  if not scores:
    return "F"

  # 1. Calculate the exact average
  average = sum(scores) / len(scores)

  # 2. Define the grading scale in an array 
  #(list of tuples) from highest to lowest
  grade_scale = [
        (97, "A+"), (93, "A"), (90, "A-"),
        (87, "B+"), (83, "B"), (80, "B-"),
        (77, "C+"), (73, "C"), (70, "C-"),
        (67, "D+"), (63, "D"), (60, "D-")
  ]

  # 3. Find the corresponding grade
  for min_score, letter_grade in grade_scale:
    if average >= min_score:
      return letter_grade

  return "F"