class_docstr: A one-dimensional frame.
  
  Frames with only a single column share certain logic that is encoded in
  this class.
docstr: Return count of unique values for the column.
  
  Parameters
  ----------
  dropna : bool, default True
      Don't include NaN in the counts.
  
  Returns
  -------
  int
      Number of unique values in the column.
docstr_tok: ["Return","count","of","unique","values","for","the","column",".","Parameters","--","--","--","--","--","dropna",":","bool",",","default","True","Do","n't","include","NaN","in","the","counts",".","Returns","--","--","--","-","int","Number","of","unique","values","in","the","column","."]
code: def nunique(self, dropna: bool = True):
      """
      Return count of unique values for the column.
  
      Parameters
      ----------
      dropna : bool, default True
          Don't include NaN in the counts.
  
      Returns
      -------
      int
          Number of unique values in the column.
      """
      if self._column.null_count == len(self):
          return 0
      return self._column.distinct_count(dropna=dropna)
  
imports: from __future__ import annotations
  import warnings
  from typing import Any, Dict, Optional, Tuple, Union
  import cupy
  import numpy
  import cudf
  from cudf._typing import Dtype, NotImplementedType, ScalarLike
  from cudf.api.extensions import no_default
  from cudf.api.types import _is_scalar_or_zero_d_array, is_bool_dtype, is_integer, is_integer_dtype
  from cudf.core.column import ColumnBase, as_column
  from cudf.core.frame import Frame
  from cudf.utils.nvtx_annotation import _cudf_nvtx_annotate
  from cudf.utils.utils import NotIterable
label_desc: Use image node_id 23 for calling the SingleColumnFrame obj's underlying member method code with example usage: obj.nunique(dropna) and returns: self, int