backward compat adjustments

Author: mlin

WDL/CLI.py

@@ -1046,8 +1046,9 @@ def runner_input(
                     -1,
                 )
                 if runtime_idx >= 0 and len(nmparts) > (runtime_idx + 1):
-                    decl = available_inputs.get(".".join(nmparts[:runtime_idx] + ["_" + override]))
-                    if decl:
+                    if decl := available_inputs.get(
+                        ".".join(nmparts[:runtime_idx] + ["_" + override])
+                    ):
                         break
 
         if not decl: