FIX: Don't fail when datatype definitions don't occur in table

src/caosadvancedtools/table_importer.py

@@ -546,6 +546,8 @@ class CSVImporter(TableImporter):
             error_dict = {}
             columns_with_errors = []
             for key, dtype in self.datatypes.items():
+                if key not in df.columns:
+                    continue
                 try:
                     df[key].astype(dtype)
                 except (TypeError, ValueError):

unittests/test_table_importer.py

@@ -398,7 +398,8 @@ class CSVImporterTest(TableImporterTest):
         kwargs = {
             "datatypes": {
                 "int": int,
-                "float": float
+                "float": float,
+                "not-in-table": str  # An unused datatype definition must not cause problems.
             },
             "obligatory_columns": ["int"],
             "converters": {}