docstr: Add the start datetime of experiment
docstr_tok: ["Add","the","start","datetime","of","experiment"]
code: def add_experiment_start(self, value):
      """
      Add the start datetime of experiment
      """
      dt = datetime.strptime(value, "%Y-%m-%d %H:%M:%S.%f")
      self.experiment_obj.experiment_start = dt
      self.experiment_obj.save()
  
imports: import json
  from settings import settings
  from datetime import datetime
  from django.utils import timezone
  from django.contrib.auth.models import AnonymousUser
  from channels.db import database_sync_to_async
  from channels.auth import login
  from channels.generic.websocket import AsyncWebsocketConsumer
  from modelchimp.models.membership import Membership
  from modelchimp.models.experiment import Experiment
  from modelchimp.enum import ClientEvent, ExperimentStatus
label_desc: Use image node_id 6 for calling the TrackerConsumer obj's underlying member method code with example usage: obj.add_experiment_start(value) without return types