adding comment

skrub/_reporting/_table_report.py

@@ -212,10 +212,15 @@ def write_html(self, file):
             with open(file, "w", encoding="utf8") as stream:
                 stream.write(html)
             return
+
         try:
+            # We don't have information about the write mode of the provided
+            # file-object. We start by writing bytes into it.
             file.write(html.encode("utf-8"))
             return
         except TypeError:
+            # We end-up here if the file-object was open in text mode
+            # Let's give it another chance in this mode.
             pass
 
         if (encoding := getattr(file, "encoding", None)) is not None:
@@ -226,7 +231,8 @@ def write_html(self, file):
                     "If `file` is a text file it should use utf-8 encoding; got:"
                     f" {encoding!r}"
                 )
-
+        # We write into the file-object expecting it to be in text mode at this
+        # stage and with a UTF-8 encoding.
         file.write(html)
 
     def open(self):

skrub/_reporting/tests/test_table_report.py

@@ -137,6 +137,8 @@ def test_write_html(tmp_path, pd_module, filename_type):
 
     tmp_file_path = tmp_path / Path("report.html")
 
+    # making sure we are closing the open files, and dealing with the first
+    # condition which doesn't require opening any file
     with contextlib.ExitStack() as stack:
         if filename_type == "str":
             filename = str(tmp_file_path)