diff --git a/src/allmydata/storage/immutable_schema.py b/src/allmydata/storage/immutable_schema.py
index 7ffec418a..440755b01 100644
--- a/src/allmydata/storage/immutable_schema.py
+++ b/src/allmydata/storage/immutable_schema.py
@@ -169,8 +169,8 @@ class _V1(object):
 
 
 ALL_SCHEMAS = {_V2, _V1}
-ALL_SCHEMA_VERSIONS = {schema.version for schema in ALL_SCHEMAS}
-NEWEST_SCHEMA_VERSION = max(ALL_SCHEMAS, key=lambda schema: schema.version)
+ALL_SCHEMA_VERSIONS = {schema.version for schema in ALL_SCHEMAS} # type: ignore
+NEWEST_SCHEMA_VERSION = max(ALL_SCHEMAS, key=lambda schema: schema.version) # type: ignore
 
 def schema_from_version(version):
     # (int) -> Optional[type]
diff --git a/src/allmydata/storage/lease.py b/src/allmydata/storage/lease.py
index 895a0970c..63dba15e8 100644
--- a/src/allmydata/storage/lease.py
+++ b/src/allmydata/storage/lease.py
@@ -252,7 +252,7 @@ class LeaseInfo(object):
 
 
 @attr.s(frozen=True)
-class HashedLeaseInfo(proxyForInterface(ILeaseInfo, "_lease_info")):
+class HashedLeaseInfo(proxyForInterface(ILeaseInfo, "_lease_info")): # type: ignore # unsupported dynamic base class
     """
     A ``HashedLeaseInfo`` wraps lease information in which the secrets have
     been hashed.