input: Write a python function to create a list of Student objects and calculate the average grade for each course.
  assert calculate_averages([('Math', [90, 80, 70]), ('Science', [85, 75, 65])])=={'Math': 80.0, 'Science': 75.0}
  assert calculate_averages([('History', [88, 92, 84]), ('Art', [78, 82, 85])])=={'History': 88.0, 'Art': 81.66666666666667}
  assert calculate_averages([('Physics', [95, 90, 85]), ('Chemistry', [80, 85, 90])])=={'Physics': 90.0, 'Chemistry': 85.0}
output: def calculate_averages(courses):
      averages = {}
      for course, grades in courses:
          averages[course] = sum(grades) / len(grades)
      return averages