diff --git a/bw_graph_tools/graph_traversal.py b/bw_graph_tools/graph_traversal.py
index 9cb3537..820a5bc 100644
--- a/bw_graph_tools/graph_traversal.py
+++ b/bw_graph_tools/graph_traversal.py
@@ -2,6 +2,7 @@
 from dataclasses import dataclass
 from functools import lru_cache
 from heapq import heappop, heappush
+from typing import Optional
 
 from bw2calc import LCA
 from scipy.sparse import spmatrix
@@ -176,13 +177,13 @@ class NewNodeEachVisitGraphTraversal:
     def calculate(
         cls,
         lca_object: LCA,
-        cutoff: float | None = 5e-3,
-        biosphere_cutoff: float | None = 1e-4,
-        max_calc: int | None = 1e5,
-        skip_coproducts: bool | None = False,
-        separate_biosphere_flows: bool | None = True,
-        static_activity_indices: set[int] | None = set(),
-        functional_unit_unique_id: int | None = -1,
+        cutoff: Optional[float] = 5e-3,
+        biosphere_cutoff: Optional[float] = 1e-4,
+        max_calc: Optional[int] = 10000,
+        skip_coproducts: Optional[bool] = False,
+        separate_biosphere_flows: Optional[bool] = True,
+        static_activity_indices: Optional[set[int]] = set(),
+        functional_unit_unique_id: Optional[int] = -1,
     ) -> dict:
         """
         Priority-first traversal (i.e. follow the past of highest score) of the supply chain graph. This class unrolls
diff --git a/bw_graph_tools/testing.py b/bw_graph_tools/testing.py
index daf15e7..1d81964 100644
--- a/bw_graph_tools/testing.py
+++ b/bw_graph_tools/testing.py
@@ -1,10 +1,11 @@
 from numbers import Number
+from typing import Union
 import numpy as np
 
 from . import Node, Edge, Flow
 
 
-def equal_dict(a: Node | Edge | Flow, b: dict, fields: list[str]):
+def equal_dict(a: Union[Node, Edge, Flow], b: dict, fields: list[str]):
     for field in fields:
         if field in b:
             if isinstance(b[field], Number):