code: def get_encrypted_field(base_class):
      
      assert not isinstance(base_class, models.Field)
      field_name = 'Encrypted' + base_class.__name__
      if base_class not in FIELD_CACHE:
          FIELD_CACHE[base_class] = type(field_name,
                                         (EncryptedMixin, base_class), {
                                             'base_class': base_class,
                                         })
      return FIELD_CACHE[base_class]
docs: A get or create method for encrypted fields, we cache the field in
      the module to avoid recreation. This also allows us to always return
      the same class reference for a field.
  
      :type base_class: models.Field[T]
      :rtype: models.Field[EncryptedMixin, T]