code: def test_fit_warm_start(self, daily_univariate_ts, backend):
      m = Prophet(stan_backend=backend).fit(
          daily_univariate_ts.iloc[:500]
      )
      m2 = Prophet(stan_backend=backend).fit(
          daily_univariate_ts.iloc[:510], init=warm_start_params(m)
      )
      assert len(m2.params["delta"][0]) == 25
  
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 TestProphetWarmStart obj's underlying member method code with example usage: obj.test_fit_warm_start(daily_univariate_ts, backend) without return types