code: def setup_method(self):
      # fit for each test, because results will be changed by test
      x = self.exog
      np.random.seed(987689)
      y = x.sum(1) + np.random.randn(x.shape[0])
      self.results = sm.WLS(y, self.exog, weights=np.ones(len(y))).fit()
  
imports: from statsmodels.compat.pandas import assert_series_equal
  from io import BytesIO
  import pickle
  import numpy
  import pandas
  import statsmodels.api
label_desc: Use image node_id 1 for calling the TestRemoveDataPickleWLS obj's underlying member method code with example usage: obj.setup_method() without return types