diff --git a/docs/guide/creating.ipynb b/docs/guide/creating.ipynb
index 92a3336..6544e89 100644
--- a/docs/guide/creating.ipynb
+++ b/docs/guide/creating.ipynb
@@ -330,6 +330,19 @@
     "indicator.name"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "<div class=\"alert alert-warning\">\n",
+    "\n",
+    "**Warning**\n",
+    "\n",
+    "Note that there are several attributes on these objects used for method names.  Accessing those will return a bound method, not the attribute value.\n",
+    "\n",
+    "</div>\n"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},
@@ -1110,21 +1123,21 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 2",
    "language": "python",
-   "name": "python3"
+   "name": "python2"
   },
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
-    "version": 3
+    "version": 2
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
-   "pygments_lexer": "ipython3",
-   "version": "3.6.7"
+   "pygments_lexer": "ipython2",
+   "version": "2.7.15"
   }
  },
  "nbformat": 4,
diff --git a/stix2/properties.py b/stix2/properties.py
index 340a4ba..3daa35b 100644
--- a/stix2/properties.py
+++ b/stix2/properties.py
@@ -11,7 +11,7 @@ from six import string_types, text_type
 
 import stix2
 
-from .base import _Observable, _STIXBase
+from .base import _STIXBase
 from .core import STIX2_OBJ_MAPS, parse, parse_observable
 from .exceptions import (
     CustomContentError, DictionaryKeyError, MissingPropertiesError,
@@ -228,19 +228,6 @@ class ListProperty(Property):
         return result
 
 
-class CallableValues(list):
-    """Wrapper to allow `values()` method on WindowsRegistryKey objects.
-    Needed because `values` is also a property.
-    """
-
-    def __init__(self, parent_instance, *args, **kwargs):
-        self.parent_instance = parent_instance
-        super(CallableValues, self).__init__(*args, **kwargs)
-
-    def __call__(self):
-        return _Observable.values(self.parent_instance)
-
-
 class StringProperty(Property):
 
     def __init__(self, **kwargs):
diff --git a/stix2/test/v20/test_observed_data.py b/stix2/test/v20/test_observed_data.py
index a822efb..bfe9c34 100644
--- a/stix2/test/v20/test_observed_data.py
+++ b/stix2/test/v20/test_observed_data.py
@@ -1301,9 +1301,9 @@ def test_windows_registry_key_example():
         values=[v],
     )
     assert w.key == "hkey_local_machine\\system\\bar\\foo"
-    assert w.values[0].name == "Foo"
-    assert w.values[0].data == "qwerty"
-    assert w.values[0].data_type == "REG_SZ"
+    assert w["values"][0].name == "Foo"
+    assert w["values"][0].data == "qwerty"
+    assert w["values"][0].data_type == "REG_SZ"
     # ensure no errors in serialization because of 'values'
     assert "Foo" in str(w)
 
diff --git a/stix2/test/v21/test_observed_data.py b/stix2/test/v21/test_observed_data.py
index c1f15cd..371018c 100644
--- a/stix2/test/v21/test_observed_data.py
+++ b/stix2/test/v21/test_observed_data.py
@@ -1382,9 +1382,9 @@ def test_windows_registry_key_example():
         values=[v],
     )
     assert w.key == "hkey_local_machine\\system\\bar\\foo"
-    assert w.values[0].name == "Foo"
-    assert w.values[0].data == "qwerty"
-    assert w.values[0].data_type == "REG_SZ"
+    assert w["values"][0].name == "Foo"
+    assert w["values"][0].data == "qwerty"
+    assert w["values"][0].data_type == "REG_SZ"
     # ensure no errors in serialization because of 'values'
     assert "Foo" in str(w)
 
diff --git a/stix2/v20/observables.py b/stix2/v20/observables.py
index dc2b4aa..81e2c48 100644
--- a/stix2/v20/observables.py
+++ b/stix2/v20/observables.py
@@ -12,7 +12,7 @@ from ..base import _Extension, _Observable, _STIXBase
 from ..custom import _custom_extension_builder, _custom_observable_builder
 from ..exceptions import AtLeastOnePropertyError, DependentPropertiesError
 from ..properties import (
-    BinaryProperty, BooleanProperty, CallableValues, DictionaryProperty,
+    BinaryProperty, BooleanProperty, DictionaryProperty,
     EmbeddedObjectProperty, EnumProperty, ExtensionsProperty, FloatProperty,
     HashesProperty, HexProperty, IntegerProperty, ListProperty,
     ObjectReferenceProperty, StringProperty, TimestampProperty, TypeProperty,
@@ -723,11 +723,6 @@ class WindowsRegistryKey(_Observable):
         ('extensions', ExtensionsProperty(spec_version="2.0", enclosing_type=_type)),
     ])
 
-    @property
-    def values(self):
-        # Needed because 'values' is a property on collections.Mapping objects
-        return CallableValues(self, self._inner['values'])
-
 
 class X509V3ExtenstionsType(_STIXBase):
     """For more detailed information on this object's properties, see
diff --git a/stix2/v21/observables.py b/stix2/v21/observables.py
index 6f53255..1703263 100644
--- a/stix2/v21/observables.py
+++ b/stix2/v21/observables.py
@@ -15,7 +15,7 @@ from ..exceptions import (
     AtLeastOnePropertyError, DependentPropertiesError, STIXDeprecationWarning,
 )
 from ..properties import (
-    BinaryProperty, BooleanProperty, CallableValues, DictionaryProperty,
+    BinaryProperty, BooleanProperty, DictionaryProperty,
     EmbeddedObjectProperty, EnumProperty, ExtensionsProperty, FloatProperty,
     HashesProperty, HexProperty, IDProperty, IntegerProperty, ListProperty,
     ObjectReferenceProperty, ReferenceProperty, StringProperty,
@@ -935,11 +935,6 @@ class WindowsRegistryKey(_Observable):
     ])
     _id_contributing_properties = ["key", "values"]
 
-    @property
-    def values(self):
-        # Needed because 'values' is a property on collections.Mapping objects
-        return CallableValues(self, self._inner['values'])
-
 
 class X509V3ExtenstionsType(_STIXBase):
     # TODO: Add link