diff --git a/cov/cov.py b/cov/cov.py
index f76eef41e4f0..1cc1b2fbc601 100644
--- a/cov/cov.py
+++ b/cov/cov.py
@@ -29,13 +29,13 @@ def decorator(func: Callable) -> Callable:
     return decorator
 
 
-def mark(branch_id: int, func_name = None) -> None:
-    if func_name is None:
-        func_name = inspect.stack()[1].function
+def mark(branch_id: int) -> None:
+    for frame in inspect.stack():
+        if frame.function in coverages:
+            coverage = coverages[frame.function]
 
-    coverage = coverages[func_name]
-
-    coverage.covered_branches[branch_id] = True
+            coverage.covered_branches[branch_id] = True
+            break
 
 
 def print_table() -> None: