code: def test_non_numerical_static_covariates(self):
      static_covs = pd.DataFrame(
          [["a", 0], ["b", 1]], columns=["cat", "num"]
      )
      assert static_covs.dtypes["num"] == "int64"
  
      ts = TimeSeries.from_values(
          values=np.random.random((10, 2))
      ).with_static_covariates(static_covs)
      assert ts.static_covariates.dtypes["num"] == ts.dtype == "float64"
      assert ts.static_covariates.dtypes["cat"] == object
  
      ts = ts.astype(np.float32)
      assert ts.static_covariates.dtypes["num"] == ts.dtype == "float32"
      assert ts.static_covariates.dtypes["cat"] == object
  
imports: import copy
  import os
  import numpy
  import pandas
  import pytest
  from darts import TimeSeries, concatenate
  from darts.dataprocessing.transformers import BoxCox, Scaler
  from darts.timeseries import DEFAULT_GLOBAL_STATIC_COV_NAME, STATIC_COV_TAG
  from darts.utils.timeseries_generation import generate_index, linear_timeseries
label_desc: Use image node_id 11 for calling the TestTimeSeriesStaticCovariate obj's underlying member method code with example usage: obj.test_non_numerical_static_covariates() without return types