Added support for XML graphs for speedy reading in

Author: jmafoster1

causal_testing/specification/causal_dag.py

@@ -134,7 +134,12 @@ def __init__(self, dot_path: str = None, ignore_cycles: bool = False, **attr):
         super().__init__(**attr)
         self.ignore_cycles = ignore_cycles
         if dot_path:
-            self.graph = nx.DiGraph(nx.nx_pydot.read_dot(dot_path))
+            if dot_path.endswith(".dot"):
+                self.graph = nx.DiGraph(nx.nx_pydot.read_dot(dot_path))
+            elif dot_path.endswith(".xml"):
+                self.graph = nx.graphml.read_graphml(dot_path)
+            else:
+                raise ValueError(f"Unsupported file extension {dot_path}. We only support .dot and .xml files.")
         else:
             self.graph = nx.DiGraph()