text: 
  
  def compute_gpa(grades, points={'A+':4.0, 'A':4.0, 'A-':3.67, 'B+':3.33,
                                  'B':3.0, 'B-':2.67,'C+':2.33, 'C':2.0,
                                  'C':1.67, 'D+':1.33, 'D':1.0, 'F':0.0}):
    num_courses = 0
    total_points = 0
    for g in grades:
      if g in points:                      # a recognizable grade
        num_courses += 1
        total_points += points[g]
    return total_points / num_courses
  