I'm new to AWS Lambda and pretty new to Python. 
I wanted to write a python lambda that uses the AWS API.
boto is the most popular python module to do this so I wanted to include it.
Looking at examples online I put import boto3 at the top of my Lambda and it just worked- I was able to use boto in my Lambda.
How does AWS know about boto? It's a community module. Are there a list of supported modules for Lambdas? Does AWS cache its own copy of community modules?
AWS Lambda's Python environment comes pre-installed with boto3. Any other libraries you want need to be part of the zip you upload. You can install them locally with pip install whatever -t mysrcfolder.
How does AWS know where my imports are?