text: 
  
  class Person:
  
      def __init__(self, initial_age):
          self.age = initial_age
  
      @property
      def age(self):
          return self._age
  
      @age.setter
      def age(self, value):
          if value < 0:
              print('Age is not valid, setting age to 0.')
              self._age = 0
          else:
              self._age = value
  
      def year_passes(self):
          self.age += 1
  
      def am_i_old(self):
          if self.age < 13:
              print('You are young.')
          elif self.age < 18:
              print('You are a teenager.')
          else:
              print('You are old.')
  
  