code: def test_invalid_regressor(
      make_weekly_data, regressor_signs, invalid_input
  ):
      train_df, test_df, coef = make_weekly_data
      regressor_col = train_df.columns.tolist()[2:]
      # make invalid values
      train_df[regressor_col[0]][36] = invalid_input
      expected_flag = False
      try:
          dlt = DLT(
              response_col="response",
              date_col="week",
              regressor_col=regressor_col,
              regressor_sign=regressor_signs,
              prediction_percentiles=[5, 95],
              seasonality=52,
              num_warmup=50,
              verbose=False,
              estimator="stan-map",
          )
          dlt.fit(train_df)
      except ModelException:
          expected_flag = True
  
      assert expected_flag
  
imports: from copy import copy
  import pytest
  import numpy
  from orbit.models import DLT
  from orbit.constants.constants import PredictionKeys
  from orbit.exceptions import ModelException, PredictionException
label_desc: Use image node_id 6 for calling a global function with example usage: test_invalid_regressor(make_weekly_data, regressor_signs, invalid_input) without return types