code: def test_constructor_dtypes_to_categorical(self, vals):
      index = Index(vals, dtype="category")
      assert isinstance(index, CategoricalIndex)
  
imports: from datetime import datetime, timedelta, timezone
  from decimal import Decimal
  import numpy
  import pytest
  from pandas._libs.tslibs.timezones import maybe_get_tz
  from pandas import NA, Categorical, CategoricalIndex, DatetimeIndex, Index, IntervalIndex, MultiIndex, NaT, PeriodIndex, Series, TimedeltaIndex, Timestamp, array, date_range, period_range, timedelta_range
  import pandas._testing
label_desc: Use image node_id 13 for calling the TestDtypeEnforced obj's underlying member method code with example usage: obj.test_constructor_dtypes_to_categorical(vals) without return types