deploy python as .zip to openwhisk

Serverless Framework
1

i would like to deploy a python function with large dependencies to ibmcloud/openwhisk as a .zip archive. This config works perfectly for aws:

service: daecc

package:
  individually: true

provider:
  name: aws
  region: us-east-1  
  runtime: python3.8
  memorySize: 128


functions:
  workers_serverless:
    handler: lambda_function.lambda_handler
    package:
      artifact: workers.zip
plugins:
  - serverless-python-requirements

If i change this config to the openwhisk syntax (python implementation, provider name & runtime, plugin) and want to try to deploy this function to ibmcloud i get the following error:

Function handler (lambda_function.py) does not exist.

Does anybody know how to deploy a python function with some large dependencies as a .zip archive to ibmcloud or is there another proper/better way?