如何将批量URL发送到grequest中？

import grequests

urls = ['http://example.com/url1', 'http://example.com/url2', 'http://example.com/url3']

requests = []

for url in urls:
    request = grequests.get(url)
    requests.append(request)

responses = grequests.map(requests)

for response in responses:
    print(response.text)