class_docstr: Interface for simple dictionary-based dataset format. The dictionary
  keys correspond to the column (i.e. dimension) names and the values
  are collections representing the values in that column.
class_docstr_tok: ["Interface","for","simple","dictionary-based","dataset","format",".","The","dictionary","keys","correspond","to","the","column","(","i.e",".","dimension",")","names","and","the","values","are","collections","representing","the","values","in","that","column","."]
code: def mask(cls, dataset, mask, mask_value=np.nan):
      masked = dict(dataset.data)
      for vd in dataset.vdims:
          new_array = np.copy(dataset.data[vd.name])
          new_array[mask] = mask_value
          masked[vd.name] = new_array
      return masked
  
imports: from collections import OrderedDict, defaultdict
  import numpy
  from ..None import util
  from ..dimension import dimension_name
  from ..element import Element
  from ..ndmapping import NdMapping, item_check, sorted_context
  from ..util import isscalar
  from .interface import DataError, Interface
label_desc: Use image node_id 12 for calling the DictInterface obj's underlying member method code with example usage: obj.mask(cls, dataset, mask, mask_value) and returns: masked