code: def get_lambda_alias_arn(app, account, region):
      
      session = boto3.Session(profile_name=account, region_name=region)
      lambda_client = session.client('lambda')
  
      lambda_aliases = lambda_client.list_aliases(FunctionName=app)
  
      matched_alias = None
      for alias in lambda_aliases['Aliases']:
          if alias['Name'] == account:
              lambda_alias_arn = alias['AliasArn']
              LOG.info('Found ARN for alias %s for function %s', account, app)
              matched_alias = lambda_alias_arn
              break
      else:
          fatal_message = 'Lambda alias {0} of function {1} not found'.format(account, app)
          LOG.fatal(fatal_message)
          raise LambdaAliasDoesNotExist(fatal_message)
      return matched_alias
docs: Get lambda alias ARN. Assumes that account name is equal to alias name.
  
      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 alias