init CRDS

csst_common/crds.py

 import functools
 import os
+
 from crds import client
 
 
@@ -69,7 +70,7 @@ class CRDS:
             d = client.api.get_file_info(self.operational_context, refs[ref_type])
             if d:
                 fp = os.path.join(self.crdsroot, "references", d["file_path"])
-                assert os.path.exists, f"File path [{fp}] does not exist!"
+                assert os.path.exists(fp), f"File path [{fp}] does not exist!"
                 refs_fp[ref_type] = fp
             else:
                 print(f"Failed to get file info for [{ref_type}:{refs[ref_type]}]")