code: def test_all_columns(simple_data):
      """
      Test that all values of the CA are
      columns.
      """
      ca = ColumnAccessor(simple_data)
      for col in ca.values():
          assert isinstance(col, cudf.core.column.ColumnBase)
  
imports: import pandas
  import pytest
  import cudf
  from cudf.core.column_accessor import ColumnAccessor
  from cudf.testing._utils import assert_eq
label_desc: Use image node_id 9 for calling a global function with example usage: test_all_columns(simple_data) without return types