text: from prophet import Prophet
  
  
  def model():
      model = Prophet(
          growth='logistic',
          yearly_seasonality=True,
          weekly_seasonality=False,
          daily_seasonality=False,
          holidays=None,
          seasonality_mode='multiplicative'
      ).add_seasonality(
          name='biannual',
          period=365.25*4,
          fourier_order=20,  # total guess
          prior_scale=5
      )
  
      return model
  