code: def mask(self) -> np.ndarray:
      return self._mask
  
imports: from operator import gt, le
  from typing import Any, List, Optional, Union
  import numpy
  import pandas
  from .errors import NoSplittableVariableException
  from .splitcondition import SplitCondition
label_desc: Use image node_id 2 for calling the CovariateMatrix obj's underlying member method code with example usage: obj.mask() and returns: self