code: def test_date_to_index_timestamp():
      dr = date_range("20000101", periods=3000, freq="W")
      y = Series(np.arange(3000.0), index=dr)
      date_index = y.index
      date = y.index[1000]
      date_pydt = date.to_pydatetime()
      date_npdt = date.to_datetime64()
      date_str = date_pydt.strftime("%Y-%m-%d")
  
      index = date_to_index(date, date_index)
      index_pydt = date_to_index(date_pydt, date_index)
      index_npdt = date_to_index(date_npdt, date_index)
      index_str = date_to_index(date_str, date_index)
      assert_equal(index, 1000)
      assert_equal(index, index_npdt)
      assert_equal(index, index_pydt)
      assert_equal(index, index_str)
  
imports: from abc import abstractmethod
  import datetime
  import numpy
  from numpy.random import RandomState
  from numpy.testing import assert_equal
  from pandas import DataFrame, Series, Timedelta, date_range
  import pytest
  from arch import doc
  from arch.univariate.base import implicit_constant
  from arch.utility.array import ConcreteClassMeta, DocStringInheritor, cutoff_to_index, date_to_index, ensure1d, ensure2d, find_index, parse_dataframe
label_desc: Use image node_id 8 for calling a global function with example usage: test_date_to_index_timestamp() without return types