  
      def __init__(self, read_only=False, write_only=False,
                   required=None, default=empty, initial=empty, source=None,
                   label=None, help_text=None, style=None,
                   error_messages=None, validators=[], allow_null=False):
          self._creation_counter = Field._creation_counter
          Field._creation_counter += 1
  
          # If `required` is unset, then use `True` unless a default is provided.
          if required is None:
 
</s> remove     def __init__(self, *args, **kwargs):
        super(ModelSerializer, self).__init__(*args, **kwargs)
        if 'validators' not in kwargs:
            validators = self.get_default_validators()
            if validators:
                self.validators.extend(validators)
                self._kwargs['validators'] = validators

 </s> add  </s> remove         self.fields = BindingDict(self)
        for key, value in self._get_base_fields().items():
            self.fields[key] = value

        self.validators = getattr(getattr(self, 'Meta', None), 'validators', [])

    def _get_base_fields(self):
 </s> add  </s> remove     def __init__(self, *args, **kwargs):
        super(Serializer, self).__init__(*args, **kwargs)

 </s> add     @property
    def fields(self):
        if not hasattr(self, '_fields'):
            self._fields = BindingDict(self)
            for key, value in self.get_fields().items():
                self._fields[key] = value
        return self._fields

    def get_fields(self):
                 error_messages=None, validators=None, allow_null=False):
  
      def __init__(self, read_only=False, write_only=False,
                   required=None, default=empty, initial=empty, source=None,
                   label=None, help_text=None, style=None,
                 error_messages=None, validators=None, allow_null=False):
          self._creation_counter = Field._creation_counter
          Field._creation_counter += 1
  
          # If `required` is unset, then use `True` unless a default is provided.
          if required is None:
keep keep keep keep replace keep keep keep keep keep
 Lazy loading of fields and validators. Closes #1963. 
rest_framework/fields.py