documentation, types, and style fixes

2 files changed, 6 insertions, 3 deletions

diff --git a/bsfs/graph/ac/base.py b/bsfs/graph/ac/base.py
index 80742d7..bc9aeb3 100644
--- a/bsfs/graph/ac/base.py
+++ b/bsfs/graph/ac/base.py
@@ -22,7 +22,11 @@ __all__: typing.Sequence[str] = (
 ## code ##
 
 class AccessControlBase(abc.ABC):
-    """
+    """Defines the interface for access control policies.
+
+    An access control policy governs which actions a user may take to query
+    or to manipulate a graph.
+
     """
 
     # The triple store backend.
diff --git a/bsfs/graph/ac/null.py b/bsfs/graph/ac/null.py
index 288a0da..36838bd 100644
--- a/bsfs/graph/ac/null.py
+++ b/bsfs/graph/ac/null.py
@@ -24,8 +24,7 @@ __all__: typing.Sequence[str] = (
 ## code ##
 
 class NullAC(base.AccessControlBase):
-    """
-    """
+    """The NULL access control implements a dummy policy that allows any action to any user."""
 
     def is_protected_predicate(self, pred: schema.Predicate) -> bool:
         """Return True if a predicate cannot be modified manually."""