diff --git a/conservancy_beancount/reconcile/helper.py b/conservancy_beancount/reconcile/helper.py
index 3ca11212abd44963ba17682703644a5a233df1e6..646efd41cca008d3d70b934974b5f80de4f946ed 100644
--- a/conservancy_beancount/reconcile/helper.py
+++ b/conservancy_beancount/reconcile/helper.py
@@ -59,7 +59,7 @@ def max_column_widths(rows: List) -> List[int]:
         return maxes
 
 
-def tabulate(rows: List, headers: List=None) -> str:
+def tabulate(rows: List, headers: List = None) -> str:
     """Format a table of data as a string.
 
     Implemented here to avoid adding dependency on "tabulate" package.