AWS Lambda function handler missing

I created the following lambda function and its given me the following error. I am new to Python and I dont think there’s anything missing in the function. can someone please help to make this function work? Thanks

import logging
import json
import boto3

client = boto3.client('workspaces')

def handler(event, context):
    response = create_workspace()
    return event
    
def create_workspace():    
    response = client.create_workspaces(
        Workspaces=[
            {
                'DirectoryId': 'd-9767328a34',
                'UserName': 'Ken',
                'BundleId': 'wsb-6cdbk8901',
                'WorkspaceProperties': {
                    'RunningMode': 'AUTO_STOP'
                },
                'Tags': [
                    {
                        'Key': 'Name',
                        'Value': 'CallCentreProvisioned'
                    },
                ]
            },
        ]
    )

Execution result

{
  "errorMessage": "Handler 'lambda_handler' missing on module 'lambda_function'",
  "errorType": "Runtime.HandlerNotFound",
  "requestId": "a09fd219-b262-4226-a04b-4d26c1b7281f",
  "stackTrace": []
}

Answer

Very simple. Rename handler to lambda_handler, or change your lambda configuration to use the handler called handler rather than lambda_handler. There were comments that mentioned this, but no simple answer given.

There is no good reason to nest the function as the other answer seems to suggest.