1 files changed, 18 insertions, 9 deletions
diff --git a/bsfs/graph/resolve.py b/bsfs/graph/resolve.py
index 4677401..a58eb67 100644
--- a/bsfs/graph/resolve.py
+++ b/bsfs/graph/resolve.py
@@ -1,9 +1,4 @@
-"""
 
-Part of the BlackStar filesystem (bsfs) module.
-A copy of the license is provided with the project.
-Author: Matthias Baumgartner, 2022
-"""
 # imports
 import typing
 
@@ -32,16 +27,30 @@ class Filter():
         input:  Any(ns.bse.tag, Is(Nodes(...)))
         output: Any(ns.bse.tag, Or(Is(...), Is(...), ...)))
 
-    >>> tags = graph.node(ns.bsfs.Tag, 'http://example.com/me/tag#1234')
-    >>> graph.get(ns.bsfs.Entity, ast.filter.Any(ns.bse.tag, ast.filter.Is(tags)))
+    >>> tags = graph.node(ns.bsn.Tag, 'http://example.com/me/tag#1234')
+    >>> graph.get(ns.bsn.Entity, ast.filter.Any(ns.bse.tag, ast.filter.Is(tags)))
 
     """
 
     def __init__(self, schema):
         self.schema = schema
 
-    def __call__(self, root_type: bsc.Node, node: ast.filter.FilterExpression):
-        # FIXME: node can be None!
+    def __call__(
+            self,
+            root_type: bsc.Node,
+            node: typing.Optional[ast.filter.FilterExpression],
+            ):
+        """Alias for `Resolve.resolve`."""
+        return self.resolve(root_type, node)
+
+    def resolve(
+            self,
+            root_type: bsc.Node,
+            node: typing.Optional[ast.filter.FilterExpression],
+            ):
+        """Resolve Nodes instances of a *node* query starting at *root_type*."""
+        if node is None:
+            return None
         return self._parse_filter_expression(root_type, node)
 
     def _parse_filter_expression(