Imrpvoe commenting

swmmanywhere/graph_utilities.py

@@ -234,9 +234,9 @@ def __call__(self,
         allowable links are specified in the `omit_edges` attribute of the 
         topology_derivation parameter. There two cases handled:
         1. The `highway` property of the edge. In osmnx, `highway` is a category
-            that contains the road type, e.g., motorway, trunk, residential. If 
-            `omit_edges` contains a value that is a category under `highway`, the
-            edge is removed.
+            that contains the road type, e.g., motorway, trunk, primary. If the
+            edge contains a value in the `highway` property that is in `omit_edges`, 
+            the edge is removed.
         2. Any other properties of the edge that are in `omit_edges`. If the 
             property is not null in the edge data, the edge is removed. e.g.,
             if `bridge` is in `omit_edges` and the `bridge` entry of the edge 

tests/test_graph_utilities.py

@@ -259,7 +259,11 @@ def test_remove_non_pipe_allowable_links():
     G = load_graph(Path(__file__).parent / 'test_data' / 'street_graph.json')
     # Ensure some invalid paths
     topology_params = parameters.TopologyDerivation(omit_edges = ['primary', 'bridge'])
+
+    # Test that an edge has a non-None 'bridge' entry
     assert len(set([d.get('bridge',None) for u,v,d in G.edges(data=True)])) > 1
+
+    # Test that an edge has a 'primary' entry under highway
     assert 'primary' in get_edge_types(G)
 
     G_ = gu.remove_non_pipe_allowable_links(G, topology_params)