以编程方式搜索GMail？

import google.auth
from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError

# 创建OAuth 2.0凭据
SCOPES = ['https://www.googleapis.com/auth/gmail.readonly']
creds = None
creds = Credentials.from_authorized_user_file('token.json', SCOPES)

if not creds or not creds.valid:
    if creds and creds.expired and creds.refresh_token:
        creds.refresh(Request())
    else:
        flow = InstalledAppFlow.from_client_secrets_file(
            'credentials.json', SCOPES)
        creds = flow.run_local_server(port=0)
    # 保存凭据
    with open('token.json', 'w') as token:
        token.write(creds.to_json())

try:
    # 构建Gmail API服务
    service = build('gmail', 'v1', credentials=creds)

    # 搜索邮件
    query = "from:example@example.com"
    results = service.users().messages().list(userId="me", q=query).execute()
    messages = results.get("messages", [])

    # 处理响应
    if not messages:
        print("No messages found.")
    else:
        print("Messages:")
        for message in messages:
            msg = service.users().messages().get(userId="me", id=message["id"]).execute()
            print(msg["snippet"])
except HttpError as error:
    print(f"An error occurred: {error}")