                  'attribute on the view correctly.' %
                  (self.__class__.__name__, self.lookup_field)
              )
  
          obj = get_object_or_404(queryset, **filter_kwargs)
  
          # May raise a permission denied
          self.check_object_permissions(self.request, obj)
  
          return obj
 
</s> remove         if lookup is not None:
            filter_kwargs = {self.lookup_field: lookup}
        elif pk is not None and self.lookup_field == 'pk':
            warnings.warn(
                'The `pk_url_kwarg` attribute is deprecated. '
                'Use the `lookup_field` attribute instead',
                DeprecationWarning
            )
            filter_kwargs = {'pk': pk}
        elif slug is not None and self.lookup_field == 'pk':
            warnings.warn(
                'The `slug_url_kwarg` attribute is deprecated. '
                'Use the `lookup_field` attribute instead',
                DeprecationWarning
            )
            filter_kwargs = {self.slug_field: slug}
        else:
 </s> add         if lookup is None: </s> remove     def get_object(self, queryset=None):
 </s> add     def get_object(self): </s> remove             exclude = _get_validation_exclusions(obj, pk, slug_field, self.lookup_field)
 </s> add             exclude = _get_validation_exclusions(obj, self.lookup_field) </s> remove         try:
            return reverse(view_name, kwargs=kwargs, request=request, format=format)
        except NoReverseMatch:
            pass

        if self.pk_url_kwarg != 'pk':
            # Only try pk if it has been explicitly set.
            # Otherwise, the default `lookup_field = 'pk'` has us covered.
            pk = obj.pk
            kwargs = {self.pk_url_kwarg: pk}
            try:
                return reverse(view_name, kwargs=kwargs, request=request, format=format)
            except NoReverseMatch:
                pass

        slug = getattr(obj, self.slug_field, None)
        if slug is not None:
            # Only try slug if it corresponds to an attribute on the object.
            kwargs = {self.slug_url_kwarg: slug}
            try:
                ret = reverse(view_name, kwargs=kwargs, request=request, format=format)
                if self.slug_field == 'slug' and self.slug_url_kwarg == 'slug':
                    # If the lookup succeeds using the default slug params,
                    # then `slug_field` is being used implicitly, and we
                    # we need to warn about the pending deprecation.
                    msg = 'Implicit slug field hyperlinked fields are deprecated.' \
                          'You should set `lookup_field=slug` on the HyperlinkedRelatedField.'
                    warnings.warn(msg, DeprecationWarning, stacklevel=2)
                return ret
            except NoReverseMatch:
                pass

        raise NoReverseMatch()
 </s> add         return reverse(view_name, kwargs=kwargs, request=request, format=format) </s> remove         try:
            return reverse(view_name, kwargs=kwargs, request=request, format=format)
        except NoReverseMatch:
            pass

        if self.pk_url_kwarg != 'pk':
            # Only try pk lookup if it has been explicitly set.
            # Otherwise, the default `lookup_field = 'pk'` has us covered.
            kwargs = {self.pk_url_kwarg: obj.pk}
            try:
                return reverse(view_name, kwargs=kwargs, request=request, format=format)
            except NoReverseMatch:
                pass

        slug = getattr(obj, self.slug_field, None)
        if slug:
            # Only use slug lookup if a slug field exists on the model
            kwargs = {self.slug_url_kwarg: slug}
            try:
                return reverse(view_name, kwargs=kwargs, request=request, format=format)
            except NoReverseMatch:
                pass

        raise NoReverseMatch()
 </s> add         return reverse(view_name, kwargs=kwargs, request=request, format=format)
        filter_kwargs = {self.lookup_field: lookup}
                  'attribute on the view correctly.' %
                  (self.__class__.__name__, self.lookup_field)
              )
  
        filter_kwargs = {self.lookup_field: lookup}
          obj = get_object_or_404(queryset, **filter_kwargs)
  
          # May raise a permission denied
          self.check_object_permissions(self.request, obj)
  
          return obj
keep keep keep add keep keep keep keep keep keep
 Remove `pk_url_field`, `slug_url_field`, `slug_field`.

Closes #1773. 
rest_framework/generics.py