Replace hasattr calls with single isinstance check.

lsst · Oct 10, 2023 · ebaca9c · ebaca9c
1 parent 1080ad2
commit ebaca9c
Showing 1 changed file with 13 additions and 17 deletions.
diff --git a/python/lsst/obs/lsst/filters.py b/python/lsst/obs/lsst/filters.py
@@ -346,36 +346,32 @@ def addFilter(filter_dict, band, physical_filter):
         if filter.physical_filter == "diffuser":
             continue
 
-        # The SDSS_65mm filters in the grating position should never be used
-        # with any filter other than "empty", so we skip those as well.
-        if hasattr(grating, "physical_filter") and filter.physical_filter != "empty":
-            continue
+        # If the grating is a FilterDefinition, use the band and alias
+        # attributes defined in the grating for the new, combined
+        # FilterDefinition. In addition, filter out any combinations that do
+        # not use the "empty" filter in combination with a grating that is a
+        # FitlerDefintion as we should never combine multiple filters in real
+        # observations.
+        if isinstance(grating, FilterDefinition):
+            if filter.physical_filter != "empty":
+                continue
 
-        # FilterDefinition is a frozen dataclass
-        if hasattr(grating, "physical_filter"):
             new_name = FILTER_DELIMITER.join([filter.physical_filter, grating.physical_filter])
-        else:
-            new_name = FILTER_DELIMITER.join([filter.physical_filter, grating])
-
-        # Also need to update aliases
-        if hasattr(grating, "physical_filter"):
             new_aliases = {FILTER_DELIMITER.join([filter.physical_filter, a]) for a in grating.alias}
-        else:
-            new_aliases = {FILTER_DELIMITER.join([a, grating]) for a in filter.alias}
 
-        # For gratings set the band to the band of the filter. If an SDSS_65mm
-        # filter is installed in the grating slot, define the band as the band
-        # of the SDSS_65mm filter.
-        if hasattr(grating, "band"):
             combo = FilterDefinition(physical_filter=new_name,
                                      band=grating.band,
                                      afw_name=grating.afw_name,
                                      alias=new_aliases)
         else:
+            new_name = FILTER_DELIMITER.join([filter.physical_filter, grating])
+            new_aliases = {FILTER_DELIMITER.join([a, grating]) for a in filter.alias}
+
             combo = FilterDefinition(physical_filter=new_name,
                                      band=filter.band,
                                      afw_name=filter.afw_name,
                                      alias=new_aliases)
+
         _latiss_filter_and_grating.append(combo)