old_contents: from faker import Faker
  import stdnum.us.ssn
  
  from scrubadub.filth.base import Filth
  
  
  class SocialSecurityNumberFilth(Filth):
      type = 'social_security_number'
  
      @staticmethod
      def generate(faker: Faker) -> str:
          """Generates an example of this ``Filth`` type, usually using the faker python library.
  
          :param faker: The ``Faker`` class from the ``faker`` library
          :type faker: Faker
          :return: An example of this ``Filth``
          :rtype: str
          """
          ssn = ''
          if faker.locales == ['en_US']:
              while not stdnum.us.ssn.is_valid(ssn):
                  ssn = faker.ssn()
          return faker.ssn()
  
new_contents: from faker import Faker
  import stdnum.us.ssn
  
  from scrubadub.filth.base import Filth
  
  
  class SocialSecurityNumberFilth(Filth):
      type = 'social_security_number'
  
      @staticmethod
      def generate(faker: Faker) -> str:
          """Generates an example of this ``Filth`` type, usually using the faker python library.
  
          :param faker: The ``Faker`` class from the ``faker`` library
          :type faker: Faker
          :return: An example of this ``Filth``
          :rtype: str
          """
          ssn = ''
          if faker.locales == ['en_US']:
              while not stdnum.us.ssn.is_valid(ssn):
                  ssn = faker.ssn()
          return faker.ssn()
  
      def is_valid(self) -> bool:
          return stdnum.us.ssn.is_valid(''.join(char for char in self.text if char not in '. -'))
  
subject: check validity of US SSNs in the associated Filth