code: def _get_none_attrs(data_arr: xr.DataArray) -> list[str]:
      """Remove attribute keys with None value."""
      return [
          attr_name
          for attr_name, attr_val in data_arr.attrs.items()
          if attr_val is None
      ]
  
imports: from __future__ import annotations
  import datetime
  import json
  import logging
  from collections import OrderedDict
  import numpy
  import xarray
  from satpy.writers.utils import flatten_dict
label_desc: Use image node_id 10 for calling a global function with example usage: _get_none_attrs(data_arr) and returns: unknown