text: import os
  import json
  import boto3
  from random import randint
  from boto3.dynamodb.conditions import Key, Attr
  
  TOTAL_NUM = 10
  CURRENT_REGION = os.environ["AWS_REGION"]
  
  def lambda_handler(event, context):
      # variables
      num_of_winners = event['num_of_winners']
      
      # query in dynamodb
      dynamodb = boto3.resource('dynamodb', region_name=CURRENT_REGION)
      table = dynamodb.Table('Lottery-Employee')
  
      # random select the winners, if has duplicate value, re-run the process
      while True:
          lottery_serials = [randint(1,TOTAL_NUM) for i in range(num_of_winners)]
          if len(lottery_serials) == len(set(lottery_serials)):
              break
      
      # retrieve the employee details from dynamodb
      results = [table.query(KeyConditionExpression=Key('lottery_serial').eq(serial), IndexName='lottery_serial-index') for serial in lottery_serials]
      
      # format results
      winner_details = [result['Items'][0] for result in results]
      
      return {
          "body": {
              "num_of_winners": num_of_winners,
              "winner_details": winner_details
          }
      }
          
      