diff --git a/stix2/registration.py b/stix2/registration.py
index 65d2714..6d426f2 100644
--- a/stix2/registration.py
+++ b/stix2/registration.py
@@ -68,9 +68,7 @@ def _register_marking(new_marking, version=DEFAULT_VERSION):
             if not re.match(PREFIX_21_REGEX, prop_name):
                 raise ValueError("Property name '%s' must begin with an alpha character." % prop_name)
 
-    class_maps = registry.get_stix2_class_maps(version)
-
-    OBJ_MAP_MARKING = class_maps['markings']
+    OBJ_MAP_MARKING = registry.STIX2_OBJ_MAPS[version]['markings']
     if mark_type in OBJ_MAP_MARKING.keys():
         raise DuplicateRegistrationError("STIX Marking", mark_type)
     OBJ_MAP_MARKING[mark_type] = new_marking
@@ -129,9 +127,7 @@ def _register_observable(new_observable, version=DEFAULT_VERSION):
                     "is not a ListProperty containing ReferenceProperty." % prop_name,
                 )
 
-    class_maps = registry.get_stix2_class_maps(version)
-
-    OBJ_MAP_OBSERVABLE = class_maps['observables']
+    OBJ_MAP_OBSERVABLE = registry.STIX2_OBJ_MAPS[version]['observables']
     if new_observable._type in OBJ_MAP_OBSERVABLE.keys():
         raise DuplicateRegistrationError("Cyber Observable", new_observable._type)
     OBJ_MAP_OBSERVABLE[new_observable._type] = new_observable
@@ -185,9 +181,8 @@ def _register_observable_extension(
             "created with the @CustomObservable decorator.",
         )
 
-    class_maps = registry.get_stix2_class_maps(version)
-    OBJ_MAP_OBSERVABLE = class_maps['observables']
-    EXT_MAP = class_maps['observable-extensions']
+    OBJ_MAP_OBSERVABLE = registry.STIX2_OBJ_MAPS[version]['observables']
+    EXT_MAP = registry.STIX2_OBJ_MAPS[version]['observable-extensions']
 
     try:
         if ext_type in EXT_MAP[observable_type].keys():
diff --git a/stix2/registry.py b/stix2/registry.py
index 3b45e48..3849913 100644
--- a/stix2/registry.py
+++ b/stix2/registry.py
@@ -42,17 +42,3 @@ def _collect_stix2_mappings():
                 ver = _stix_vid_to_version(stix_vid)
                 mod = importlib.import_module(name, str(top_level_module.__name__))
                 STIX2_OBJ_MAPS[ver]['markings'] = mod.OBJ_MAP_MARKING
-
-
-def get_stix2_class_maps(stix_version):
-    """
-    Get the stix2 class mappings for the given STIX version.
-
-    :param stix_version: A STIX version as a string
-    :return: The class mappings.  This will be a dict mapping from some general
-        category name, e.g. "object" to another mapping from STIX type
-        to a stix2 class.
-    """
-    cls_maps = STIX2_OBJ_MAPS[stix_version]
-
-    return cls_maps
diff --git a/stix2/utils.py b/stix2/utils.py
index 34915d9..c44dbe1 100644
--- a/stix2/utils.py
+++ b/stix2/utils.py
@@ -350,7 +350,7 @@ def is_sdo(value, stix_version=stix2.DEFAULT_VERSION):
     :return: True if the type of the given value is an SDO type; False
         if not
     """
-    cls_maps = mappings.get_stix2_class_maps(stix_version)
+    cls_maps = mappings.STIX2_OBJ_MAPS[stix_version]
     type_ = _stix_type_of(value)
     result = type_ in cls_maps["objects"] and type_ not in {
         "relationship", "sighting", "marking-definition", "bundle",
@@ -370,7 +370,7 @@ def is_sco(value, stix_version=stix2.DEFAULT_VERSION):
     :return: True if the type of the given value is an SCO type; False
         if not
     """
-    cls_maps = mappings.get_stix2_class_maps(stix_version)
+    cls_maps = mappings.STIX2_OBJ_MAPS[stix_version]
     type_ = _stix_type_of(value)
     result = type_ in cls_maps["observables"]
 
@@ -406,7 +406,7 @@ def is_object(value, stix_version=stix2.DEFAULT_VERSION):
     :return: True if the type of the given value is a valid STIX type with
         respect to the given STIX version; False if not
     """
-    cls_maps = mappings.get_stix2_class_maps(stix_version)
+    cls_maps = mappings.STIX2_OBJ_MAPS[stix_version]
     type_ = _stix_type_of(value)
     result = type_ in cls_maps["observables"] or type_ in cls_maps["objects"]