Testing Python "Hello World" in AWS Lambda

I will apologies first hand if my question formatting is messed up. A noob programmer here

I was following steps defined in the AWS Lambda Developer Guide to run the Hello World code. Ref Page 44

def my_handler(event, context):
    message = 'Hello {} {}!'.format(event['first_name'],
                                    event['last_name'])
    return {
        'message' : message
}     

Test error in AWS

I believe my error is that the code is looking for events but the input test event on the test page is providing 3 key values which have no relation to my code.

testpage