swh.lister.gitlab: Improve headers extraction

swh/lister/utils.py

@@ -0,0 +1,14 @@
+# Copyright (C) 2018 the Software Heritage developers
+# License: GNU General Public License version 3, or any later version
+# See top-level LICENSE file for more information
+
+
+def get(d, keys):
+    """Given a dict, lookup in order for keys with values not None.
+
+    """
+    for key in keys:
+        v = d.get(key)
+        if v is not None:
+            return v
+    return None