code: def test_fourier_series_weekly(self, daily_univariate_ts):
      mat = Prophet.fourier_series(daily_univariate_ts["ds"], 7, 3)
      # These are from the R forecast package directly.
      true_values = np.array(
          [
              0.7818315,
              0.6234898,
              0.9749279,
              -0.2225209,
              0.4338837,
              -0.9009689,
          ]
      )
      assert np.sum((mat[0] - true_values) ** 2) == pytest.approx(0.0)
  
imports: import numpy
  import pandas
  import pytest
  from prophet import Prophet
  from prophet.utilities import warm_start_params
label_desc: Use image node_id 1 for calling the TestProphetSeasonalComponent obj's underlying member method code with example usage: obj.test_fourier_series_weekly(daily_univariate_ts) without return types