code: def _get_unique(column, dummy_na):
      """
      Returns unique values in a column, if
      dummy_na is False, nan's are also dropped.
      """
      if isinstance(column, cudf.core.column.CategoricalColumn):
          unique = column.categories
      else:
          unique = column.unique().sort_values()
      if not dummy_na:
          if np.issubdtype(unique.dtype, np.floating):
              unique = unique.nans_to_nulls()
          unique = unique.dropna()
      return unique
  
imports: import itertools
  import warnings
  from collections import abc
  from typing import Dict, Optional
  import cupy
  import numpy
  import pandas
  import cudf
  from cudf._lib.transform import one_hot_encode
  from cudf._lib.types import size_type_dtype
  from cudf._typing import Dtype
  from cudf.api.extensions import no_default
  from cudf.core.column import ColumnBase, as_column, column_empty_like
  from cudf.core.column.categorical import CategoricalColumn
  from cudf.utils.dtypes import min_unsigned_type
label_desc: Use image node_id 11 for calling a global function with example usage: _get_unique(column, dummy_na) and returns: unique