[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

scripts/convert_NWP_grib_to_zarr.py

@@ -459,7 +459,7 @@ def post_process_dataset(dataset: xr.Dataset) -> xr.Dataset:
     logger.debug("Post-processing dataset...")
     da = dataset.to_array(dim="variable", name="UKV")
 
-    assert len(da['variables']) <= len(NWP_VARIABLE_NAMES)
+    assert len(da["variables"]) <= len(NWP_VARIABLE_NAMES)
     # to_array looks like it can sometimes change the order of the variables.
     # So fix the order:
     # If some variables are missing, then reindexing will simply set those as NaN.