diff --git a/music21/analysis/reduction.py b/music21/analysis/reduction.py
index e1bdab51f..fa7551973 100644
--- a/music21/analysis/reduction.py
+++ b/music21/analysis/reduction.py
@@ -286,12 +286,12 @@ def _extractNoteReductiveEvent(self, n, infoDict=None, removeAfterParsing=True):
             return
 
         removalIndices = []
-        if m.hasElement(n):
+        if n in m:
             offset = n.getOffsetBySite(m)
         else:  # it is in a Voice
             offset = 0.0
             for v in m.voices:
-                if v.hasElement(n):
+                if n in v:
                     offset = n.getOffsetBySite(v)
 
 
diff --git a/music21/freezeThaw.py b/music21/freezeThaw.py
index 2b08ed999..5701785f8 100644
--- a/music21/freezeThaw.py
+++ b/music21/freezeThaw.py
@@ -1193,8 +1193,8 @@ def testSerializationScaffoldA(self):
         sf.setupSerializationScaffold()
 
         # test safety
-        self.assertTrue(s2.hasElement(n1))
-        self.assertTrue(s1.hasElement(n1))
+        self.assertTrue(n1 in s2)
+        self.assertTrue(n1 in s1)
 
     def testJSONPickleSpanner(self):
         from music21 import converter
diff --git a/music21/stream/base.py b/music21/stream/base.py
index d484f8655..aaa732754 100644
--- a/music21/stream/base.py
+++ b/music21/stream/base.py
@@ -1436,8 +1436,9 @@ def mergeAttributes(self, other: base.Music21Object):
                      'definesExplicitPageBreaks', '_atSoundingPitch', '_mutable'):
             if hasattr(other, attr):
                 setattr(self, attr, getattr(other, attr))
-                
-    @deprecated('v10', 'v11', 'use `obj in stream` instead')
+
+    @common.deprecated('v10', 'v11', 'Use `el in stream` instead of '
+                       '`stream.hasElement(el)`')
     def hasElement(self, obj: base.Music21Object) -> bool:
         '''
         Return True if an element, provided as an argument, is contained in
@@ -2008,7 +2009,7 @@ def _deepcopySubclassable(self: StreamType,
         # must manually add elements to new Stream
         for e in self._elements:
             # environLocal.printDebug(['deepcopy()', e, 'old', old, 'id(old)', id(old),
-            #     'new', new, 'id(new)', id(new), 'old.hasElement(e)', old.hasElement(e),
+            #     'new', new, 'id(new)', id(new), 'e in old', e in old,
             #     'e.activeSite', e.activeSite, 'e.getSites()', e.getSites(), 'e.getSiteIds()',
             #     e.getSiteIds()], format='block')
             #
diff --git a/music21/test/test_base.py b/music21/test/test_base.py
index de1bc0df6..7f0ea16fc 100644
--- a/music21/test/test_base.py
+++ b/music21/test/test_base.py
@@ -570,14 +570,14 @@ def testStoreLastDeepCopyOf(self):
         n2 = copy.deepcopy(n1)
         self.assertEqual(id(n2.derivation.origin), id(n1))
 
-    def testHasElement(self):
+    def testContains(self):
         n1 = note.Note()
         s1 = stream.Stream()
         s1.append(n1)
         s2 = copy.deepcopy(s1)
         n2 = s2[0]  # this is a new instance; not the same as n1
-        self.assertFalse(s2.hasElement(n1))
-        self.assertTrue(s2.hasElement(n2))
+        self.assertFalse(n1 in s2)
+        self.assertTrue(n2 in s2)
 
         self.assertFalse(s1 in n2.sites)
         self.assertTrue(s2 in n2.sites)
@@ -622,7 +622,7 @@ class Mock:
             s.insert(i, el)
 
         for ew in storage:
-            self.assertTrue(s.hasElement(ew))
+            self.assertTrue(ew in s)
 
         match = [e.getOffsetBySite(s) for e in storage]
         self.assertEqual(match, [0.0, 1.0])
@@ -648,7 +648,7 @@ def getnchannels(self):
             s.insert(i, el)
 
         for ew in storage:
-            self.assertTrue(s.hasElement(ew))
+            self.assertTrue(ew in s)
 
         matchOffset = []
         matchBeatStrength = []