4 files changed, 10 insertions, 10 deletions
diff --git a/lib/sqlalchemy/orm/attributes.py b/lib/sqlalchemy/orm/attributes.py
index b0f10c20b..5cc9cb309 100644
--- a/lib/sqlalchemy/orm/attributes.py
+++ b/lib/sqlalchemy/orm/attributes.py
@@ -12,10 +12,10 @@ from sqlalchemy.orm import interfaces, collections
 from sqlalchemy.orm.util import identity_equal
 from sqlalchemy import exceptions
 
-PASSIVE_NORESULT = object()
-ATTR_WAS_SET = object()
-NO_VALUE = object()
-NEVER_SET = object()
+PASSIVE_NORESULT = util.symbol('PASSIVE_NORESULT')
+ATTR_WAS_SET = util.symbol('ATTR_WAS_SET')
+NO_VALUE = util.symbol('NO_VALUE')
+NEVER_SET = util.symbol('NEVER_SET')
 
 class InstrumentedAttribute(interfaces.PropComparator):
     """public-facing instrumented attribute, placed in the
diff --git a/lib/sqlalchemy/orm/collections.py b/lib/sqlalchemy/orm/collections.py
index 8f04fdf7a..7b78c240b 100644
--- a/lib/sqlalchemy/orm/collections.py
+++ b/lib/sqlalchemy/orm/collections.py
@@ -1011,7 +1011,7 @@ def _dict_decorators():
         setattr(fn, '_sa_instrumented', True)
         fn.__doc__ = getattr(getattr(dict, fn.__name__), '__doc__')
 
-    Unspecified=object()
+    Unspecified=sautil.symbol('Unspecified')
 
     def __setitem__(fn):
         def __setitem__(self, key, value, _sa_initiator=None):
@@ -1107,7 +1107,7 @@ def _set_decorators():
         setattr(fn, '_sa_instrumented', True)
         fn.__doc__ = getattr(getattr(Set, fn.__name__), '__doc__')
 
-    Unspecified=object()
+    Unspecified=sautil.symbol('Unspecified')
 
     def add(fn):
         def add(self, value, _sa_initiator=None):
diff --git a/lib/sqlalchemy/orm/interfaces.py b/lib/sqlalchemy/orm/interfaces.py
index f510a3ffa..15f752314 100644
--- a/lib/sqlalchemy/orm/interfaces.py
+++ b/lib/sqlalchemy/orm/interfaces.py
@@ -14,7 +14,7 @@ ORM.
 """
 
 from itertools import chain
-from sqlalchemy import exceptions, logging
+from sqlalchemy import exceptions, logging, util
 from sqlalchemy.sql import expression
 class_mapper = None
 
@@ -24,8 +24,8 @@ __all__ = ['EXT_CONTINUE', 'EXT_STOP', 'EXT_PASS', 'MapperExtension',
            'ExtensionOption', 'PropertyOption',
            'AttributeExtension', 'StrategizedOption', 'LoaderStrategy' ]
 
-EXT_CONTINUE = EXT_PASS = object()
-EXT_STOP = object()
+EXT_CONTINUE = EXT_PASS = util.symbol('EXT_CONTINUE')
+EXT_STOP = util.symbol('EXT_STOP')
 
 class MapperExtension(object):
     """Base implementation for customizing Mapper behavior.
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index c0a15c427..62067fc35 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -30,7 +30,7 @@ global_extensions = []
 # a constant returned by _get_attr_by_column to indicate
 # this mapper is not handling an attribute for a particular
 # column
-NO_ATTRIBUTE = object()
+NO_ATTRIBUTE = util.symbol('NO_ATTRIBUTE')
 
 # lock used to synchronize the "mapper compile" step
 _COMPILE_MUTEX = util.threading.Lock()