code: def test_regressor_coefficients(self, daily_univariate_ts, backend):
      m = Prophet(stan_backend=backend)
      df = daily_univariate_ts.copy()
      np.random.seed(123)
      df["regr1"] = np.random.normal(size=df.shape[0])
      df["regr2"] = np.random.normal(size=df.shape[0])
      m.add_regressor("regr1", mode="additive")
      m.add_regressor("regr2", mode="multiplicative")
      m.fit(df)
  
      coefs = regressor_coefficients(m)
      assert coefs.shape == (2, 6)
      # No MCMC sampling, so lower and upper should be the same as mean
      assert np.array_equal(
          coefs["coef_lower"].values, coefs["coef"].values
      )
      assert np.array_equal(
          coefs["coef_upper"].values, coefs["coef"].values
      )
  
imports: import numpy
  from prophet import Prophet
  from prophet.utilities import regressor_coefficients
label_desc: Use image node_id 1 for calling the TestUtilities obj's underlying member method code with example usage: obj.test_regressor_coefficients(daily_univariate_ts, backend) without return types