code: def dtype(cls, dataset, dim):
      name = dataset.get_dimension(dim, strict=True).name
      if cls.packed(dataset) and name in dataset.vdims:
          return dataset.data.dtype
      return dataset.data[name].dtype
  
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 4 for calling the XArrayInterface obj's underlying member method code with example usage: obj.dtype(cls, dataset, dim) and returns: dataset, dataset