changed list to explicit copy, which is not supported by python 3.10

src/toargridding/metadata.py

@@ -28,8 +28,7 @@ Variables = Enum("Variables", [*DATA_VARIABLES, *COORDINATE_VARIABLES])
 TIME_FREQUENCIES = {"daily": "D", "monthly": "M", "yearly": "Y"}  # TODO test
 
 DATA_AGGREGATION_MODES = ["meanTSbyStation", "mergedTS", None]
-
-DataAggregationModes = Literal[*DATA_AGGREGATION_MODES]
+DataAggregationModes = Literal["meanTSbyStation", "mergedTS", None]
 
 @dataclass
 class TimeSample: