diff --git a/Lib/ldap/modlist.py b/Lib/ldap/modlist.py
index 4acf4e9..bf4e481 100644
--- a/Lib/ldap/modlist.py
+++ b/Lib/ldap/modlist.py
@@ -50,7 +50,7 @@ def modifyModlist(
   case_ignore_attr_types = {v.lower() for v in case_ignore_attr_types or []}
   modlist = []
   attrtype_lower_map = {}
-  for a in old_entry.keys():
+  for a in old_entry:
     attrtype_lower_map[a.lower()]=a
   for attrtype, value in new_entry.items():
     attrtype_lower = attrtype.lower()
diff --git a/Lib/ldap/schema/subentry.py b/Lib/ldap/schema/subentry.py
index 5ccbce0..215f148 100644
--- a/Lib/ldap/schema/subentry.py
+++ b/Lib/ldap/schema/subentry.py
@@ -23,7 +23,7 @@
     SCHEMA_CLASS_MAPPING[o.schema_attribute] = o
     SCHEMA_ATTR_MAPPING[o] = o.schema_attribute
 
-SCHEMA_ATTRS = SCHEMA_CLASS_MAPPING.keys()
+SCHEMA_ATTRS = list(SCHEMA_CLASS_MAPPING)
 
 
 class SubschemaError(ValueError):
@@ -122,7 +122,7 @@ def __init__(self,sub_schema_sub_entry,check_uniqueness=1):
         self.sed[se_class][se_id] = se_instance
 
         if hasattr(se_instance,'names'):
-          for name in ldap.cidict.cidict({}.fromkeys(se_instance.names)).keys():
+          for name in ldap.cidict.cidict({}.fromkeys(se_instance.names)):
             if check_uniqueness and name in self.name2oid[se_class]:
               self.non_unique_names[se_class][se_id] = None
               raise NameNotUnique(attr_value)
@@ -130,7 +130,7 @@ def __init__(self,sub_schema_sub_entry,check_uniqueness=1):
               self.name2oid[se_class][name] = se_id
 
     # Turn dict into list maybe more handy for applications
-    self.non_unique_oids = self.non_unique_oids.keys()
+    self.non_unique_oids = list(self.non_unique_oids)
 
     return # subSchema.__init__()
 
@@ -168,7 +168,7 @@ def listall(self,schema_element_class,schema_element_filters=None):
           except AttributeError:
             pass
     else:
-      result = avail_se.keys()
+      result = list(avail_se)
     return result
 
 
@@ -422,14 +422,14 @@ def attribute_types(
 
     # Remove all mandantory attribute types from
     # optional attribute type list
-    for a in list(r_may.keys()):
+    for a in list(r_may):
       if a in r_must:
         del r_may[a]
 
     # Apply attr_type_filter to results
     if attr_type_filter:
       for l in [r_must,r_may]:
-        for a in list(l.keys()):
+        for a in list(l):
           for afk,afv in attr_type_filter:
             try:
               schema_attr_type = self.sed[AttributeType][a]
diff --git a/Tests/t_ldap_syncrepl.py b/Tests/t_ldap_syncrepl.py
index 73ba1fb..9398de5 100644
--- a/Tests/t_ldap_syncrepl.py
+++ b/Tests/t_ldap_syncrepl.py
@@ -242,7 +242,7 @@ def syncrepl_present(self, uuids, refreshDeletes=False):
 
         elif (uuids is None) and (refreshDeletes is False):
             deleted_uuids = []
-            for uuid in self.uuid_dn.keys():
+            for uuid in self.uuid_dn:
                 if uuid not in self.present:
                     deleted_uuids.append(uuid)