Only check keys if menmonic has more than one version

src/toolbox_scs/mnemonics_machinery.py

@@ -10,6 +10,7 @@ import logging
 
 from .constants import mnemonics as _mnemonics
 from extra_data import open_run
+from numpy import s_
 __all__ = [
     'mnemonics_for_run'
 ]
@@ -72,6 +73,8 @@ def mnemo_version_index(run, mnemonic):
         The index of the tuple. If no valid version is found, returns -1.
 
     """
+    if len(_mnemonics[mnemonic]) == 1:
+        return 0
     for i, v in enumerate(_mnemonics[mnemonic]):
         if (v['source'] in run.all_sources and
                 v['key'] in run.keys_for_source(v['source'])):