fix when gh2_dim is not in dataset

src/toolbox_scs/detectors/gotthard2.py

@@ -53,7 +53,7 @@ def extract_GH2(ds, run, firstFrame=0, bunchPattern='scs_ppl',
         pattern = XrayPulses(run)
         dim = 'sa3_pId'
     others = [var for var in ds if dim in ds[var].coords]
-    nds = ds.drop_dims(dim)
+    nds = ds.drop_dims(dim, errors='ignore')
     if pattern.is_constant_pattern():
         pulse_ids = pattern.peek_pulse_ids(labelled=False)
         nds = nds.isel({gh2_dim: pulse_ids + firstFrame})