code: def test_weighted_selection_router():
      # this tests if load balancing works based on the provided rpms in the router
      # it's a fast test, only tests get_available_deployment
      # users can pass rpms as a litellm_param
      try:
          litellm.set_verbose = False
          model_list = [
              {
                  "model_name": "gpt-3.5-turbo",
                  "litellm_params": {
                      "model": "gpt-3.5-turbo-0613",
                      "api_key": os.getenv("OPENAI_API_KEY"),
                      "rpm": 6,
                  },
              },
              {
                  "model_name": "gpt-3.5-turbo",
                  "litellm_params": {
                      "model": "azure/chatgpt-v-2",
                      "api_key": os.getenv("AZURE_API_KEY"),
                      "api_base": os.getenv("AZURE_API_BASE"),
                      "api_version": os.getenv("AZURE_API_VERSION"),
                      "rpm": 1440,
                  },
              },
          ]
          router = Router(
              model_list=model_list,
          )
          selection_counts = defaultdict(int)
  
          # call get_available_deployment 1k times, it should pick azure/chatgpt-v-2 about 90% of the time
          for _ in range(1000):
              selected_model = router.get_available_deployment(
                  "gpt-3.5-turbo"
              )
              selected_model_id = selected_model["litellm_params"][
                  "model"
              ]
              selected_model_name = selected_model_id
              selection_counts[selected_model_name] += 1
          print(selection_counts)
  
          total_requests = sum(selection_counts.values())
  
          # Assert that 'azure/chatgpt-v-2' has about 90% of the total requests
          assert (
              selection_counts["azure/chatgpt-v-2"] / total_requests
              > 0.89
          ), f"Assertion failed: 'azure/chatgpt-v-2' does not have about 90% of the total requests in the weighted load balancer. Selection counts {selection_counts}"
  
          router.reset()
      except Exception as e:
          traceback.print_exc()
          pytest.fail(f"Error occurred: {e}")
  
file_path: litellm/litellm/tests/test_router_get_deployments.py
imports: import sys, os, time
  import traceback, asyncio
  import pytest
  import litellm
  from litellm import Router
  from concurrent.futures import ThreadPoolExecutor
  from collections import defaultdict
  from dotenv import load_dotenv
label_desc: Use image node_id 1 for calling a global function with example usage: test_weighted_selection_router() without return types