code: def mask(cls, dataset, mask, mask_value=np.nan):
      masked = np.copy(dataset.data)
      masked[mask] = mask_value
      return masked
  
imports: import numpy
  from ..None import util
  from ..dimension import dimension_name
  from ..element import Element
  from ..ndmapping import NdMapping, item_check, sorted_context
  from .interface import DataError, Interface
label_desc: Use image node_id 10 for calling the ArrayInterface obj's underlying member method code with example usage: obj.mask(cls, dataset, mask, mask_value) and returns: masked