  from rest_framework.fields import Field, WritableField, get_component, is_simple_callable
  from rest_framework.reverse import reverse
  from rest_framework.compat import urlparse
  from rest_framework.compat import smart_text
  import warnings
  
  
  # Relational fields
  
  # Not actually Writable, but subclasses may need to be.
 
</s> remove import warnings
 </s> add  </s> remove def _get_validation_exclusions(obj, pk=None, slug_field=None, lookup_field=None):
 </s> add def _get_validation_exclusions(obj, lookup_field=None): </s> remove         # Determine the base queryset to use.
        if queryset is None:
            queryset = self.filter_queryset(self.get_queryset())
        else:
            pass  # Deprecation warning
 </s> add         queryset = self.filter_queryset(self.get_queryset()) </s> remove     def get_object(self, queryset=None):
 </s> add     def get_object(self): </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)
  from rest_framework.fields import Field, WritableField, get_component, is_simple_callable
  from rest_framework.reverse import reverse
  from rest_framework.compat import urlparse
  from rest_framework.compat import smart_text

  
  
  # Relational fields
  
  # Not actually Writable, but subclasses may need to be.
keep keep keep keep replace keep keep keep keep keep
 Remove `pk_url_field`, `slug_url_field`, `slug_field`.

Closes #1773. 
rest_framework/relations.py