code: def num_masked_target_values(
      data: Dict[str, np.ndarray]
  ) -> np.ndarray:
      if np.ma.isMaskedArray(data["label"]):
          assert isinstance(data["label"], np.ma.MaskedArray)
          return data["label"].mask.astype(float)
      else:
          return np.zeros(data["label"].shape)
  
file_path: gluonts/src/gluonts/ev/stats.py
imports: from typing import Dict
  import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: num_masked_target_values(data) and returns: data, np