code: def is_scalar_nan(x):
      return bool(isinstance(x, numbers.Real) and np.isnan(x))
  
imports: from ....internals import _deprecate_pos_args
  from ....common.array_descriptor import CumlArrayDescriptor
  from ....internals.array_sparse import SparseCumlArray
  from ..utils.validation import FLOAT_DTYPES
  from ..utils.validation import check_is_fitted
  from cuml.internals.mixins import AllowNaNTagMixin, SparseInputTagMixin, StringInputTagMixin
  from ..utils.skl_dependencies import BaseEstimator, TransformerMixin
  from ....thirdparty_adapters import _get_mask, _masked_column_median, _masked_column_mean, _masked_column_mode
  from cuml.internals.safe_imports import gpu_only_import_from
  import cuml
  from cuml.internals.safe_imports import gpu_only_import
  import numbers
  import warnings
  from cuml.internals.safe_imports import cpu_only_import
label_desc: Use image node_id 1 for calling a global function with example usage: is_scalar_nan(x) and returns: bool