text: students = []
  
  class Student:
  
      # initializer
      def __init__(self, name, id = 0, age = 0):
          self.name = name
          self.id = id
          if (age < 0):
              raise ValueError(f"Age cannot be less than zero {age}")
          self._age = age
  
          students.append(self)
  
      # override toString
      def __str__(self):
          return "Student {0}'s id is {1} and age is {2}".format(self.name.capitalize(), self.id, self.age)
  
      # define age property
      def age(self):
          return self.age
  
  mark = Student("mark")
  jack = Student("jack", 101, 10) # Change age to -ve to raise an exception
  
  print(mark)
  print(jack)