code: def test_init():
      """Tests instantiation."""
      model = QuantileRegressionUncertaintyModel(uncertainty_dict={})
      assert model.coverage is None
      assert model.time_col is None
      assert model.uncertainty_dict == {}
      assert model.is_residual_based is None
      assert model.x_mat is None
      assert model.build_x_mat is None
      assert model.value_col is None
      assert model.residual_col is None
      assert model.quantiles is None
      assert model.models is None
      assert model.distribution_col is None
      assert model.offset_col is None
  
file_path: greykite/greykite/tests/sklearn/uncertainty/test_quantile_regression_uncertainty_model.py
imports: import pandas
  import pytest
  from greykite.common import constants
  from greykite.common.data_loader import DataLoader
  from greykite.sklearn.estimator.simple_silverkite_estimator import SimpleSilverkiteEstimator
  from greykite.sklearn.uncertainty.exceptions import UncertaintyError
  from greykite.sklearn.uncertainty.quantile_regression_uncertainty_model import QuantileRegressionUncertaintyModel
label_desc: Use image node_id 2 for calling a global function with example usage: test_init() without return types