added back in return statement that was inadvertently removed

Author: tclose

pydra/engine/core.py

@@ -943,6 +943,7 @@ def _sanitize_spec(
                 raise ValueError("Provided SpecInfo must have BaseSpec as its base.")
             if "_graph_checksums" not in {f[0] for f in spec.fields}:
                 spec.fields.insert(0, graph_checksum_input)
+            return spec
         else:
             base = BaseSpec
             if isinstance(spec, list):

pydra/engine/tests/test_workflow.py

@@ -69,7 +69,7 @@ def test_wf_specinfo_input_spec():
         bases=(ShellSpec,),
     )
     with pytest.raises(
-        ValueError, match="Provided SpecInfo must have BaseSpec as it's base."
+        ValueError, match="Provided SpecInfo must have BaseSpec as its base."
     ):
         Workflow(name="workflow", input_spec=bad_input_spec)