EC2 Auto Stop

 import boto3
 import logging

 #setup simple logging for INFO
 logger = logging.getLogger()
 logger.setLevel(logging.INFO)

 #define the connection and set the region
 ec2 = boto3.resource('ec2', region_name='ap-southeast-1')

 def lambda_handler(event, context):

     # all running EC2 instances.
     filters = [{
             'Name': 'tag:AutoStop',
             'Values': ['True']
         },
         {
             'Name': 'instance-state-name', 
             'Values': ['running']
         }
     ]

     #filter the instances which are stopped
     instances = ec2.instances.filter(Filters=filters)

     #locate all running instances
     RunningInstances = [instance.id for instance in instances]

     #print the instances for logging purposes
     #print RunningInstances 

     if len(RunningInstances) > 0:
         #perform the shutdown
         shuttingDown = ec2.instances.filter(InstanceIds=RunningInstances).stop()
         print(shuttingDown)
     else:
         print("Nothing to see here")