generative-ai-python AttributeError: module 'google.generativeai' has no attribute 'Tool' on a fresh environment

Description of the bug:

Body:

Hello,

I am encountering a persistent AttributeError: module 'google.generativeai' has no attribute 'Tool' even after extensive debugging, including a full virtual environment rebuild. The import path for the module appears to be correct, but the Tool attribute cannot be found.

Goal: I am trying to use Function Calling with the Gemini API by defining a genai.Tool.
The Error:

Traceback (most recent call last):
  File "create_issue.py", line 58, in <module>
    genai.Tool(
    ^^^^^^^^^^
AttributeError: module 'google.generativeai' has no attribute 'Tool'

System & Library Information:OS: Windows (using PowerShell)pip show google-generativeai output:

Name: google-generativeai
Version: 0.8.5
Location: C:\Users\09801\Desktop\fountion coding\venv\Lib\site-packages
Import Path Check (genai.__file__ output):
C:\Users\09801\Desktop\fountion coding\venv\Lib\site-packages\google\generativeai\__init__.py

Code (create_issue.py): Python

import os
import requests
import google.generativeai as genai

# --- 1. Key Configuration ---
try:
    genai.configure(api_key=os.environ["GOOGLE_API_KEY"])
    GITHUB_TOKEN = os.environ["GITHUB_TOKEN"]
    GITHUB_REPO = os.environ["GITHUB_REPO"]
except KeyError:
    print("Error: Environment variables not set.")
    exit()

# --- 2. Function Definition ---
def create_github_issue(title: str, body: str, labels: list[str] = None):
    # Function code... (as provided before)
    pass

# --- 3. Model and Tool Setup ---
tools = [
    genai.Tool(
        function_declarations=[
            genai.FunctionDeclaration.from_func(create_github_issue)
        ]
    )
]

model = genai.GenerativeModel(
    model_name="gemini-1.5-flash",
    tools=tools
)

print("Model and tools configured.")

Troubleshooting Steps Taken:

Confirmed library is up-to-date (v0.8.5). Rebuilt the virtual environment from scratch (rm -rf venv, python -m venv venv, pip install ...). Forced re-install without cache (pip install --force-reinstall --no-cache-dir ...). Confirmed there is no local file named google.py that would cause a namespace collision. Confirmed the module import path is correct using genai.file. Despite all these steps, the AttributeError persists, suggesting a deeper issue with the library or its dependencies on my specific system. Any help would be appreciated.