code: def mask(cls, dataset, mask, mask_val=np.nan):
      packed = cls.packed(dataset)
      masked = dataset.data.copy()
      if packed:
          data_coords = list(dataset.data.dims)[:-1]
          mask = cls.canonicalize(dataset, mask, data_coords)
          try:
              masked.values[mask] = mask_val
          except ValueError:
              masked = masked.astype("float")
              masked.values[mask] = mask_val
      else:
          orig_mask = mask
          for vd in dataset.vdims:
              dims = list(dataset.data[vd.name].dims)
              if any(
                  cls.irregular(dataset, kd) for kd in dataset.kdims
              ):
                  data_coords = dims
              else:
                  data_coords = [kd.name for kd in dataset.kdims][::-1]
              mask = cls.canonicalize(dataset, orig_mask, data_coords)
              if data_coords != dims:
                  inds = [dims.index(d) for d in data_coords]
                  mask = mask.transpose(inds)
              masked[vd.name] = marr = masked[vd.name].astype("float")
              marr.values[mask] = mask_val
      return masked
  
imports: import sys
  import types
  import numpy
  import pandas
  from ..None import util
  from ..dimension import Dimension, asdim, dimension_name
  from ..element import Element
  from ..ndmapping import NdMapping, item_check, sorted_context
  from .grid import GridInterface
  from .interface import DataError, Interface
  from .util import dask_array_module, finite_range
label_desc: Use image node_id 22 for calling the XArrayInterface obj's underlying member method code with example usage: obj.mask(cls, dataset, mask, mask_val) and returns: masked