diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index fd8af2c0cedd0..7f94e741c57ba 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -22,6 +22,7 @@
     cast,
     final,
     overload,
+    Union,
 )
 import warnings
 import weakref
@@ -3337,7 +3338,7 @@ def to_latex(
     @doc(storage_options=_shared_docs["storage_options"])
     def to_csv(
         self,
-        path_or_buf: FilePathOrBuffer[AnyStr] | None = None,
+        path_or_buf: Union[FilePathOrBuffer[AnyStr], None] = None,
         sep: str = ",",
         na_rep: str = "",
         float_format: str | None = None,