From 02228b175d50091266d11e830eafdffb76d309a5 Mon Sep 17 00:00:00 2001
From: yohplala <pierre.juillard@gmail.com>
Date: Wed, 21 Aug 2024 18:31:13 +0200
Subject: [PATCH] More robustness when dealing with pandas column multi-index.

---
 oups/store/writer.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/oups/store/writer.py b/oups/store/writer.py
index 45d7ba8..8f22042 100644
--- a/oups/store/writer.py
+++ b/oups/store/writer.py
@@ -229,13 +229,14 @@ def check_cmidx(chunk):
 
     Most notably, fastparquet requires names for each level in a Multiindex.
     If these are not set, there are set to '', an empty string.
+    Also, column names have to be tuple of string.
 
-    Multiindex is modified in-place.
+    DataFrame is modified in-place.
 
     Parameters
     ----------
     chunk : DataFrame
-        DataFrame which multi-index is to check.
+        DataFrame with a column multi-index to check and possibly adjust.
 
     Returns
     -------