first commit

.venv/Lib/site-packages/authlib/common/language.py

@@ -0,0 +1,13 @@
+import re
+
+# Structurally validates BCP 47 language tags (RFC 5646).
+# Accepts private-use tags (x-...) and standard tags (2-8 alpha + optional subtags).
+# Does not validate subtags against the IANA registry.
+_LANGUAGE_TAG_RE = re.compile(
+    r"^(x(-[a-zA-Z0-9]{1,8})+|[a-zA-Z]{2,8}(-[a-zA-Z0-9]{1,8})*)$"
+)
+
+
+def is_valid_language_tag(tag):
+    """Return True if tag is a structurally valid BCP 47 language tag."""
+    return isinstance(tag, str) and bool(_LANGUAGE_TAG_RE.match(tag))