title: AWS Lambda function firing twice
body: <p>I'm using an AWS Lambda function (written in python) to send an email whenever an object is uploaded into a preset S3 bucket. The object is uploaded via the AWS PHP SDK into the S3 bucket and is using a multipart upload. Whenever I test out my code (within the Lambda code editor page) it seems to work fine and I only get a single email.</p>
  
  <p>But when the object is uploaded via the PHP SDK, the Lambda function runs twice and sends two emails, both with different message ID's. I've tried different email addresses but each address receives exactly two, duplicate emails.</p>
  
  <p>Can anyone guide me where could I be going wrong? I'm using the boto3 library that is imported with the sample python code to send the email.</p>