code: def get_lambda_arn(app, account, region):
      
      session = boto3.Session(profile_name=account, region_name=region)
      lambda_client = session.client('lambda')
  
      lambda_arn = None
      paginator = lambda_client.get_paginator('list_functions')
  
      for lambda_functions in paginator.paginate():
          for lambda_function in lambda_functions['Functions']:
              if lambda_function['FunctionName'] == app:
                  lambda_arn = lambda_function['FunctionArn']
                  LOG.debug("Lambda ARN for lambda function %s is %s.", app, lambda_arn)
                  break
          if lambda_arn:
              break
  
      if not lambda_arn:
          LOG.fatal('Lambda function with name %s not found in %s %s', app, account, region)
          raise LambdaFunctionDoesNotExist(
              'Lambda function with name {0} not found in {1} {2}'.format(app, account, region))
  
      return lambda_arn
docs: Get lambda ARN.
  
      Args:
          account (str): AWS account name.
          region (str): Region name, e.g. us-east-1
          app (str): Lambda function name
  
      Returns:
          str: ARN for requested lambda function