code: def test_flat_growth(self, backend, scaling):
      m = Prophet(growth="flat", stan_backend=backend, scaling=scaling)
      x = np.linspace(0, 2 * np.pi, 8 * 7)
      history = pd.DataFrame(
          {
              "ds": pd.date_range(
                  start="2020-01-01", periods=8 * 7, freq="d"
              ),
              "y": 30 + np.sin(x * 8.0),
          }
      )
      m.fit(history)
      future = m.make_future_dataframe(10, include_history=True)
      fcst = m.predict(future)
      m_ = m.params["m"][0, 0]
      k = m.params["k"][0, 0]
      assert k == pytest.approx(0.0)
      assert fcst["trend"].unique()[0] == pytest.approx(
          (m_ * m.y_scale) + m.y_min
      )
      assert np.round((m_ * m.y_scale) + m.y_min) == 30.0
  
imports: import numpy
  import pandas
  import pytest
  from prophet import Prophet
  from prophet.utilities import warm_start_params
label_desc: Use image node_id 4 for calling the TestProphetTrendComponent obj's underlying member method code with example usage: obj.test_flat_growth(backend, scaling) without return types