remove very old deprecated method

docs/changelog.rst

@@ -13,7 +13,8 @@ Changes in 0.19.1
 - Requires Pillow < 7.0.0 as it dropped Python2 support
 - DEPRECATION: The interface of ``QuerySet.aggregate`` method was changed, it no longer takes an unpacked list of
     pipeline steps (*pipeline) but simply takes the pipeline list just like ``pymongo.Collection.aggregate`` does. #2079
-
+- BREAKING CHANGE: Removed Queryset._ensure_indexes and Queryset.ensure_indexes that were deprecated in 2013.
+    Document.ensure_indexes still exists
 Changes in 0.19.0
 =================
 - BREAKING CHANGE: ``class_check`` and ``read_preference`` keyword arguments are no longer available when filtering a ``QuerySet``. #2112

mongoengine/queryset/base.py

@@ -1958,23 +1958,3 @@ class BaseQuerySet(object):
         setattr(queryset, "_" + method_name, val)
 
         return queryset
-
-    # Deprecated
-    def ensure_index(self, **kwargs):
-        """Deprecated use :func:`Document.ensure_index`"""
-        msg = (
-            "Doc.objects()._ensure_index() is deprecated. "
-            "Use Doc.ensure_index() instead."
-        )
-        warnings.warn(msg, DeprecationWarning)
-        self._document.__class__.ensure_index(**kwargs)
-        return self
-
-    def _ensure_indexes(self):
-        """Deprecated use :func:`~Document.ensure_indexes`"""
-        msg = (
-            "Doc.objects()._ensure_indexes() is deprecated. "
-            "Use Doc.ensure_indexes() instead."
-        )
-        warnings.warn(msg, DeprecationWarning)
-        self._document.__class__.ensure_indexes()