From 3512e2f321e6b81a45579910ac2c8b26517d3219 Mon Sep 17 00:00:00 2001
From: foreverseer <1923212756@qq.com>
Date: Tue, 16 Nov 2021 09:24:54 +0800
Subject: [PATCH 1/3] avoid a warning by PyTypeChecker

NDFrame.to_csv(str) got a warning by PyTypeChecker, "Expected type 'None', got 'str' instead"
use typing.Union to combine type "FilePathOrBuffer[AnyStr]" and "None", instead of " | " can avoid it.
---
 pandas/core/generic.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index fd8af2c0cedd0..4a4e77958c690 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -22,7 +22,7 @@
     cast,
     final,
     overload,
-)
+),Union
 import warnings
 import weakref
 
@@ -3337,7 +3337,7 @@ 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,

From e9a80e1c94658858442b3dc50adb01d56d6ea006 Mon Sep 17 00:00:00 2001
From: foreverseer <1923212756@qq.com>
Date: Tue, 16 Nov 2021 09:35:14 +0800
Subject: [PATCH 2/3] add whitespace after ','

---
 pandas/core/generic.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 4a4e77958c690..13bfbdfefb01b 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -22,7 +22,7 @@
     cast,
     final,
     overload,
-),Union
+), Union
 import warnings
 import weakref
 
@@ -3337,7 +3337,7 @@ def to_latex(
     @doc(storage_options=_shared_docs["storage_options"])
     def to_csv(
         self,
-        path_or_buf: Union[FilePathOrBuffer[AnyStr],None] = None,
+        path_or_buf: Union[FilePathOrBuffer[AnyStr], None] = None,
         sep: str = ",",
         na_rep: str = "",
         float_format: str | None = None,

From ca2078db2c7b8e580413f1a0b4c85166aa1f0ed5 Mon Sep 17 00:00:00 2001
From: foreverseer <1923212756@qq.com>
Date: Tue, 16 Nov 2021 09:40:12 +0800
Subject: [PATCH 3/3] fix a error

"from typing import Union " with wrong place in last commit
---
 pandas/core/generic.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 13bfbdfefb01b..7f94e741c57ba 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -22,7 +22,8 @@
     cast,
     final,
     overload,
-), Union
+    Union,
+)
 import warnings
 import weakref