class_docstr: Report Manager Base class
  Inherited classes should override:
      * `_report_training`
      * `_report_step`
class_docstr_tok: ["Report","Manager","Base","class","Inherited","classes","should","override",":","*","`","_report_training","`","*","`","_report_step","`"]
code: def start(self):
      self.start_time = time.time()
  
imports: import time
  from datetime import datetime
  import onmt
  from onmt.utils.logging import logger
label_desc: Use image node_id 2 for calling the ReportMgrBase obj's underlying member method code with example usage: obj.start() without return types