code: def test_widget_client_df_datetime(self, rename_libraries):
      import perspective
  
      assert perspective.is_libpsp() is False
      data = pd.DataFrame(
          {
              "a": [
                  datetime(2020, i, 1, 12, 30, 45) for i in range(1, 13)
              ]
          },
          dtype="datetime64[ns]",
      )
      widget = perspective.PerspectiveWidget(data)
      assert hasattr(widget, "table") is False
      assert widget._data == {
          "index": [i for i in range(12)],
          "a": [
              "2020-{:02d}-01 12:30:45".format(i) for i in range(1, 13)
          ],
      }
  
imports: import os
  import pytest
  import sys
  import numpy
  import pandas
  from datetime import date, datetime
  from functools import partial
  from types import MethodType
label_desc: Use image node_id 12 for calling the TestClient obj's underlying member method code with example usage: obj.test_widget_client_df_datetime(rename_libraries) without return types