code: def test_ordinary_quantile_regression(data):
      """Tests ordinary quantile regression."""
      coef = ordinary_quantile_regression(
          x=np.concatenate(
              [data["x"], np.ones([len(data["x"]), 1])], axis=1
          ),
          y=data["y"],
          q=0.1,
          sample_weight=np.ones(len(data["y"])),
          max_iter=200,
          tol=1e-3,
      )
      pred = (
          np.concatenate(
              [data["x"], np.ones([len(data["x"]), 1])], axis=1
          )
          @ coef
      )
      coef1 = ordinary_quantile_regression(
          x=np.concatenate(
              [data["x"], np.ones([len(data["x"]), 1])], axis=1
          ),
          y=data["y"],
          q=0.9,
          sample_weight=np.ones(len(data["y"])),
          max_iter=200,
          tol=1e-3,
      )
      pred1 = (
          np.concatenate(
              [data["x"], np.ones([len(data["x"]), 1])], axis=1
          )
          @ coef1
      )
      assert all(pred1 > pred)
  
file_path: greykite/greykite/tests/algo/common/test_l1_quantile_regression.py
imports: import numpy
  import pytest
  from testfixtures import LogCapture
  from greykite.algo.common.l1_quantile_regression import QuantileRegression
  from greykite.algo.common.l1_quantile_regression import l1_quantile_regression
  from greykite.algo.common.l1_quantile_regression import ordinary_quantile_regression
  from greykite.common.logging import LOGGER_NAME
label_desc: Use image node_id 2 for calling a global function with example usage: test_ordinary_quantile_regression(data) without return types