draft: sketched out SO interface CI workflow.

.github/workflows/interface_ci.yml

@@ -0,0 +1,13 @@
+name: interface-ci
+on: [pull_request]
+jobs:
+  checks-so-interface:
+    runs-on: ubuntu-latest
+    defaults:
+        run:
+          working-directory: ./tests/ci
+    steps:
+        - name: Check out the repository to the runner
+          uses: actions/checkout@v4
+        - name: Check SO interface spec
+          run: python ./check_so_interface.py

python/pysmurf/client/base/smurf_config.py

@@ -442,7 +442,7 @@ def validate_config(loaded_config):
 
                 # data_out_mux
                 Optional("data_out_mux",
-                         default=default_data_out_mux_dict[band]) : \
+                         default=default_data_out_mux_dict[band]) :
                 And([Use(int)], list, lambda l: len(l) == 2 and
                     l[0] != l[1] and all(0 <= ll <= 9 for ll in l)),