minor style fixes

3 files changed, 8 insertions, 7 deletions

diff --git a/bsfs/graph/resolve.py b/bsfs/graph/resolve.py
index 0ba1e36..95dcfc1 100644
--- a/bsfs/graph/resolve.py
+++ b/bsfs/graph/resolve.py
@@ -48,6 +48,7 @@ class Filter():
             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)
diff --git a/bsfs/query/validator.py b/bsfs/query/validator.py
index b259ea0..1ce44e9 100644
--- a/bsfs/query/validator.py
+++ b/bsfs/query/validator.py
@@ -36,11 +36,11 @@ class Filter():
     def __init__(self, schema: bsc.Schema):
         self.schema = schema
 
-    def __call__(self, root_type: bsc.Node, query: ast.filter.FilterExpression):
+    def __call__(self, root_type: bsc.Node, query: ast.filter.FilterExpression) -> bool:
         """Alias for `Filter.validate`."""
         return self.validate(root_type, query)
 
-    def validate(self, root_type: bsc.Node, query: ast.filter.FilterExpression):
+    def validate(self, root_type: bsc.Node, query: ast.filter.FilterExpression) -> bool:
         """Validate a filter *query*, assuming the subject having *root_type*.
 
         Raises a `bsfs.utils.errors.ConsistencyError` if the query violates the schema.
@@ -241,11 +241,11 @@ class Fetch():
     def __init__(self, schema: bsc.Schema):
         self.schema = schema
 
-    def __call__(self, root_type: bsc.Node, query: ast.filter.FilterExpression):
+    def __call__(self, root_type: bsc.Node, query: ast.fetch.FetchExpression) -> bool:
         """Alias for `Fetch.validate`."""
         return self.validate(root_type, query)
 
-    def validate(self, root_type: bsc.Node, query: ast.fetch.FetchExpression):
+    def validate(self, root_type: bsc.Node, query: ast.fetch.FetchExpression) -> bool:
         """Validate a fetch *query*, assuming the subject having *root_type*.
 
         Raises a `bsfs.utils.errors.ConsistencyError` if the query violates the schema.
diff --git a/bsfs/triple_store/sparql/parse_filter.py b/bsfs/triple_store/sparql/parse_filter.py
index bf19a02..2f5a25b 100644
--- a/bsfs/triple_store/sparql/parse_filter.py
+++ b/bsfs/triple_store/sparql/parse_filter.py
@@ -151,16 +151,16 @@ class Filter():
             raise errors.BackendError(f'the range of predicate {pred} is undefined')
         dom, rng = pred.domain, pred.range
         # encapsulate predicate uri
-        puri = f'<{puri}>' # type: ignore [assignment] # variable re-use confuses mypy
+        uri_str = f'<{puri}>'
         # apply reverse flag
         if node.reverse:
-            puri = '^' + puri
+            uri_str = '^' + uri_str
             dom, rng = rng, dom # type: ignore [assignment] # variable re-use confuses mypy
         # check path consistency
         if not node_type <= dom:
             raise errors.ConsistencyError(f'expected type {dom} or subtype thereof, found {node_type}')
         # return predicate URI and next node type
-        return puri, rng
+        return uri_str, rng
 
     def _any(self, node_type: bsc.Vertex, node: ast.filter.Any, head: str) -> str:
         """