API需要设置回调URL，获取授权码后，用授权码和API秘钥向API服务器请求访问令牌，再将令牌作为参数访问API。

代码示例：

import requests
import json

# 设置API授权信息
api_key = 'your_api_key'
api_secret = 'your_api_secret'
callback_url = 'http://your_callback_url'

# 获取授权码
response = requests.get('https://api.example.com/oauth/authorize', params={
    'client_id': api_key,
    'redirect_uri': callback_url,
    'response_type': 'code'
})

# 获取访问令牌
auth_code = 'your_auth_code'
response = requests.post('https://api.example.com/oauth/token', data={
    'grant_type': 'authorization_code',
    'client_id': api_key,
    'client_secret': api_secret,
    'redirect_uri': callback_url,
    'code': auth_code
})

access_token = json.loads(response.text)['access_token']

# 访问API
response = requests.get('https://api.example.com/data', headers={
    'Authorization': 'Bearer ' + access_token
})

data = json.loads(response.text)