From 64aafbb88c5d1782b541ead31482627d818bf020 Mon Sep 17 00:00:00 2001
From: "Gerber, Mike" <mike.gerber@sbb.spk-berlin.de>
Date: Thu, 7 Aug 2025 20:29:40 +0200
Subject: [PATCH] =?UTF-8?q?=F0=9F=A7=B9=20MODS:=20Handle=20mods:languageTe?=
 =?UTF-8?q?rm=20with=20authority=3Diso639-2/rfc3066?=
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Content-Type: text/plain; charset=UTF-8
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---
 src/mods4pandas/lib.py         | 12 ++++++++++++
 src/mods4pandas/mods4pandas.py |  1 +
 2 files changed, 13 insertions(+)

diff --git a/src/mods4pandas/lib.py b/src/mods4pandas/lib.py
index fed3a01..45f50e8 100644
--- a/src/mods4pandas/lib.py
+++ b/src/mods4pandas/lib.py
@@ -187,6 +187,18 @@ class TagGroup:
                 warnings.warn("Changed scriptTerm authority to lower case")
         return self
 
+    def fix_language_term(self) -> TagGroup:
+        for e in self.group:
+            if e.attrib["authority"] == "iso639-2":
+                e.attrib["authority"] = "iso639-2b"
+                warnings.warn("Changed languageTerm authority to iso639-2b")
+            if e.attrib["authority"] == "rfc3066":
+                if e.text == "de":
+                    e.attrib["authority"] = "iso639-2b"
+                    e.text = "deu"
+                    warnings.warn("Changed languageTerm authority from rfc3066 to iso639-2b")
+        return self
+
     def add_missing_type_text(self) -> TagGroup:
         for e in self.group:
             if not e.attrib.get("type") == "text":
diff --git a/src/mods4pandas/mods4pandas.py b/src/mods4pandas/mods4pandas.py
index 888aba4..1c0d48a 100755
--- a/src/mods4pandas/mods4pandas.py
+++ b/src/mods4pandas/mods4pandas.py
@@ -255,6 +255,7 @@ def mods_to_dict(mods, raise_errors=True):
         elif tag == "{http://www.loc.gov/mods/v3}languageTerm":
             value["languageTerm"] = (
                 TagGroup(tag, group)
+                .fix_language_term()
                 .has_attributes({"authority": "iso639-2b", "type": "code"})
                 .text_set()
             )