From 073adf3986f8e8ad3dabe481baccbcf8de8caa21 Mon Sep 17 00:00:00 2001
From: Dobson <bdobson@ic.ac.uk>
Date: Fri, 5 Apr 2024 10:35:26 +0100
Subject: [PATCH] Update graph_utilities.py

make proper graphfcn
---
 swmmanywhere/graph_utilities.py | 50 ++++++++++++++++++---------------
 1 file changed, 28 insertions(+), 22 deletions(-)

diff --git a/swmmanywhere/graph_utilities.py b/swmmanywhere/graph_utilities.py
index e697677e..8ccecc79 100644
--- a/swmmanywhere/graph_utilities.py
+++ b/swmmanywhere/graph_utilities.py
@@ -222,31 +222,37 @@ def __call__(self,
         return G
     
 @register_graphfcn
-def remove_parallels(G: nx.MultiDiGraph, weight = 'length') -> nx.DiGraph:
-    """Remove parallel edges from a street network.
+class remove_isolated_nodes(BaseGraphFunction):
+    """remove_isolated_nodes class."""
 
-    Retain the edge with the smallest weight (i.e., length).
+    def __call__(self, G: nx.Graph, **kwargs) -> nx.Graph:
+        """Remove parallel edges from a street network.
 
-    Args:
-        G (nx.MultiDiGraph): A graph.
-        weight (str): The edge attribute to use as the weight.
-    
-    Returns:
-        G (nx.DiGraph): The graph with parallel edges removed.
+        Retain the edge with the smallest weight (i.e., length).
 
-    Author:
-        Taher Chegini
-    """
-    graph = ox.get_digraph(G)
-    _, _, attr_list = next(iter(graph.edges(data=True)))  # type: ignore
-    attr_list = cast("dict[str, Any]", attr_list)
-    if weight not in attr_list:
-        raise ValueError(f"{weight} not in edge attributes.")
-    attr = nx.get_node_attributes(graph, weight)
-    parallels = (e for e in attr if e[::-1] in attr)
-    graph.remove_edges_from({e if attr[e] > attr[e[::-1]] 
-                             else e[::-1] for e in parallels})
-    return graph
+        Args:
+            G (nx.MultiDiGraph): A graph.
+            **kwargs: Additional keyword arguments are ignored.
+        
+        Returns:
+            G (nx.DiGraph): The graph with parallel edges removed.
+
+        Author:
+            Taher Chegini
+        """
+        # Set the attribute (weight) used to determine which parallel edge to
+        # retain. Could make this a parameter in parameters.py if needed.
+        weight = 'length' 
+        graph = ox.get_digraph(G)
+        _, _, attr_list = next(iter(graph.edges(data=True)))  # type: ignore
+        attr_list = cast("dict[str, Any]", attr_list)
+        if weight not in attr_list:
+            raise ValueError(f"{weight} not in edge attributes.")
+        attr = nx.get_node_attributes(graph, weight)
+        parallels = (e for e in attr if e[::-1] in attr)
+        graph.remove_edges_from({e if attr[e] > attr[e[::-1]] 
+                                else e[::-1] for e in parallels})
+        return graph
 
 @register_graphfcn
 class format_osmnx_lanes(BaseGraphFunction,