AWS Python 3.7 Lambda using boto3: workmailmessageflow - UnknownServiceError

Question

Following the sample code provided in the boto3 documentation for using the workmailmessageflow service

import boto3

client = boto3.client('workmailmessageflow')

triggers and UnknownServiceError: "Unknown service: 'workmailmessageflow'. Valid service names are..."

The boto3 version reported by AWS Lambda Python 3.7 is 1.9.221. Any thoughts on why workmailmessageflow is not recognized?

Ref: https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/workmailmessageflow.html

Answer 1

Because workmailmessageflow first appeared in Boto3 1.9.228. You have to use a custom version of Boto3, either use a layer or package the latest version together with your code.