diff --git a/python/obitools3/uri/decode.pyx b/python/obitools3/uri/decode.pyx
index 3cf95c6..c0c38b7 100644
--- a/python/obitools3/uri/decode.pyx
+++ b/python/obitools3/uri/decode.pyx
@@ -386,10 +386,13 @@ def open_uri(uri,
             raise MalformedURIException('Malformed header argument in URI')
        
         if b"sep" in qualifiers:
-            sep=tobytes(qualifiers[b"sep"][0][0])
+            sep = tobytes(qualifiers[b"sep"][0][0])
         else:
             try:
-                sep=tobytes(config["obi"]["sep"])
+                sep = config["obi"]["sep"]
+                if sep == '\\t':   # dirty workaround for flake8(?) issue that reads '\t' as '\'+'t' when parsing the option value
+                    sep = '\t'
+                sep = tobytes(sep)
             except KeyError:
                 sep=None