docstr: Only fit the data without validation data
  
  :param data: training data, an dataframe with Td rows,
      and 2 columns, with column 'ds' indicating date and column 'y' indicating target
      and Td is the time dimension
docstr_tok: ["Only","fit","the","data","without","validation","data",":","param","data",":","training","data",",","an","dataframe","with","Td","rows",",","and","2","columns",",","with","column","'ds","'","indicating","date","and","column","'","y","'","indicating","target","and","Td","is","the","time","dimension"]
code: def _fit(self, data, **config):
      """
      Only fit the data without validation data
  
      :param data: training data, an dataframe with Td rows,
          and 2 columns, with column 'ds' indicating date and column 'y' indicating target
          and Td is the time dimension
      """
      if not self.model_init:
          self._build(**config)
          self.model_init = True
  
      self.model.fit(data)
  
file_path: BigDL/python/chronos/src/bigdl/chronos/model/prophet.py
imports: import json
  import numpy
  from prophet import Prophet
  from prophet.serialize import model_to_json, model_from_json
  from prophet.diagnostics import performance_metrics
  from prophet.diagnostics import cross_validation
  from bigdl.chronos.metric.forecast_metrics import Evaluator
label_desc: Use image node_id 3 for calling the ProphetModel obj's underlying member method code with example usage: obj._fit(data) without return types