input: Write a python function to classify students based on their marks.
  assert classify_data([{'Name': 'Alice', 'Marks': 65}, {'Name': 'Bob', 'Marks': 75}, {'Name': 'Charlie', 'Marks': 95}]) == [{'Name': 'Alice', 'Marks': 65, 'Class': 'Average'}, {'Name': 'Bob', 'Marks': 75, 'Class': 'Good'}, {'Name': 'Charlie', 'Marks': 95, 'Class': 'Excellent'}]
  assert classify_data([{'Name': 'David', 'Marks': 50}, {'Name': 'Eve', 'Marks': 85}, {'Name': 'Frank', 'Marks': 90}]) == [{'Name': 'David', 'Marks': 50, 'Class': 'Average'}, {'Name': 'Eve', 'Marks': 85, 'Class': 'Good'}, {'Name': 'Frank', 'Marks': 90, 'Class': 'Excellent'}]
  assert classify_data([{'Name': 'Grace', 'Marks': 70}, {'Name': 'Heidi', 'Marks': 89}, {'Name': 'Ivan', 'Marks': 91}]) == [{'Name': 'Grace', 'Marks': 70, 'Class': 'Good'}, {'Name': 'Heidi', 'Marks': 89, 'Class': 'Good'}, {'Name': 'Ivan', 'Marks': 91, 'Class': 'Excellent'}]
output: def classify_data(students):
      for student in students:
          marks = student['Marks']
          if marks >= 90:
              student['Class'] = 'Excellent'
          elif marks >= 70:
              student['Class'] = 'Good'
          else:
              student['Class'] = 'Average'
      return students