code: def start(ctx, alias, description, f):
      
      today = datetime.date.today()
  
      try:
          timesheet_collection = get_timesheet_collection_for_context(ctx, f)
      except ParseError as e:
          ctx.obj['view'].err(e)
          return
  
      t = timesheet_collection.latest()
  
      # If there's a previous entry on the same date, check if we can use its
      # end time as a start time for the newly started entry
      today_entries = t.entries.filter(date=today)
      if(today in today_entries and today_entries[today]
              and isinstance(today_entries[today][-1].duration, tuple)
              and today_entries[today][-1].duration[1] is not None):
          new_entry_start_time = today_entries[today][-1].duration[1]
      else:
          new_entry_start_time = datetime.datetime.now()
  
      description = ' '.join(description) if description else '?'
      duration = (new_entry_start_time, None)
  
      e = Entry(alias, duration, description)
      t.entries[today].append(e)
      t.save()
docs: Use it when you start working on the given activity. This will add the
      activity and the current time to your entries file. When you're finished,
      use the stop command.