code: def test_lm_weights(self):
      p = (
          self.p
          + aes(weight="x.abs()")
          + stat_smooth(
              method="lm", formula="y ~ np.sin(x)", fill="red", se=True
          )
      )
      assert p == "lm_formula_weights"
  
imports: import numpy
  import pandas
  import pytest
  import statsmodels.api
  from plotnine import aes, coord_trans, geom_point, geom_smooth, ggplot, stat_smooth
  from plotnine.exceptions import PlotnineWarning
label_desc: Use image node_id 2 for calling the TestFormula obj's underlying member method code with example usage: obj.test_lm_weights() without return types