尝试向pypi api发出请求时出现403错误

我的代码：

import requests

x = requests.get('http://pypi.python.org/pypi/urllib3/json')

print(x)

输出：

<Response [403]>

为什么即使在浏览器中工作正常，我也会收到此响应？

我试图打印 json：

import requests

x = requests.get('http://pypi.python.org/pypi/urllib3/json')

print(x.json())

但它给了我一个错误：

Traceback (most recent call last):
  File "C:\Users\HP\Desktop\temp.py", line 5, in <module>
    print(x.json())
  File "C:\Users\HP\AppData\Local\Packages\PythonSoftwareFoundation.Python.3.9_qbz5n2kfra8p0\LocalCache\local-packages\Python39\site-packages\requests\models.py", line 900, in json
    return complexjson.loads(self.text, **kwargs)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.9_3.9.1776.0_x64__qbz5n2kfra8p0\lib\json\__init__.py", line 346, in loads
    return _default_decoder.decode(s)
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.9_3.9.1776.0_x64__qbz5n2kfra8p0\lib\json\decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "C:\Program Files\WindowsApps\PythonSoftwareFoundation.Python.3.9_3.9.1776.0_x64__qbz5n2kfra8p0\lib\json\decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)