code: def test_params_only(basic_data, method):
      y, x, _ = basic_data
      mod = RollingOLS(y, x, 150)
      res = mod.fit(method=method, params_only=False)
      res_params_only = mod.fit(method=method, params_only=True)
      # use assert_allclose to incorporate for numerical errors on x86 platforms
      assert_allclose(res_params_only.params, res.params)
  
imports: from io import BytesIO
  from itertools import product
  import warnings
  import numpy
  import pandas
  import pytest
  from numpy.testing import assert_allclose, assert_array_equal
  from statsmodels import tools
  from statsmodels.regression.linear_model import WLS
  from statsmodels.regression.rolling import RollingWLS, RollingOLS
label_desc: Use image node_id 16 for calling a global function with example usage: test_params_only(basic_data, method) without return types