Import libraries in lambda layers

I wanted to import jsonschema library in my AWS Lambda in order to perform request validation. Instead of bundling the dependency with my app , I am looking to do this via Lambda Layers. I zipped all the dependencies under venv/lib/python3.6/site-packages/. I uploaded this as a lambda layer and added it to my aws lambda using publish-layer-version and aws lambda update-function-configuration commands respectively. The zip folder is name "lambda-dep.zip" and all the files are under it. However when I try to import jsonschema in my lambda_function , I see the error below -

from jsonschema import validate

{"errorMessage": "Unable to import module 'lambda_api': No module named 'jsonschema'","errorType": "Runtime.ImportModuleError"}

Am I missing any steps are is there a different mechanism to import anything within lambda layers?