FIX: deal with nonexisting obligatory

src/caosadvancedtools/table_importer.py

@@ -374,7 +374,8 @@ class TableImporter():
         for index, row in df.iterrows():
             # if none of the relevant information is given, skip
 
-            if np.array([pd.isnull(row.loc[key]) for key in self.obligatory_columns]).all():
+            if np.array([pd.isnull(row.loc[key]) for key in self.obligatory_columns
+                         if key in df.columns]).all():
 
                 df = df.drop(index)