error/warning on duplicate mapping keys0.15.1

1 files changed, 10 insertions, 0 deletions

diff --git a/compat.py b/compat.py
index c9f6373..7f3434f 100644
--- a/compat.py
+++ b/compat.py
@@ -180,3 +180,13 @@ def check_anchorname_char(ch):
     if ch in u',[]{}':
         return False
     return check_namespace_char(ch)
+
+
+def version_tnf(t1, t2=None):
+    # type: (Any, Any) -> Any
+    from ruamel.yaml import version_info  # NOQA
+    if version_info < t1:
+        return True
+    if t2 is not None and version_info < t2:
+        return None
+    return False