context-var.py

"""
data_layer.py - how to use the credentials
"""
from decorators import get_dynamodb_session_keys

def some_data_access_method():
   session = boto3.Session(**get_dynamodb_session_keys())
   dynamodb = session.resource("dynamodb")
   table = dynamodb.Table(TABLE_NAME)
   # now we can use 'table' to access with tenant_id restrictions

And then hooking it all together into our handler file:

"""
handler.py - applying to our lambda
"""
from decorators import dynamodb_tenant_isolation

@dynamodb_tenant_isolation
def handler(event, context):
   # our lambda code