code: def test_subdaily_holidays(self, subdaily_univariate_ts, backend):
      holidays = pd.DataFrame(
          {
              "ds": pd.to_datetime(["2017-01-02"]),
              "holiday": ["special_day"],
          }
      )
      m = Prophet(holidays=holidays, stan_backend=backend)
      m.fit(subdaily_univariate_ts)
      fcst = m.predict()
      assert sum(fcst["special_day"] == 0) == 575
  
imports: import numpy
  import pandas
  import pytest
  from prophet import Prophet
  from prophet.utilities import warm_start_params
label_desc: Use image node_id 7 for calling the TestProphetHolidays obj's underlying member method code with example usage: obj.test_subdaily_holidays(subdaily_univariate_ts, backend) without return types