我想更新 conda 以获取更高版本的 python 及其扩展，但它一直告诉我：
(base) C:\Users\pierr>conda update conda
Solving environment: done
==> WARNING: A newer version of conda exists. <==
current version: 4.5.2
latest version: 4.5.4
Please update conda by running
$ conda update -n base conda
# All requested packages already installed.
(base) C:\Users\pierr>conda update -n base conda
Solving environment: done
==> WARNING: A newer version of conda exists. <==
current version: 4.5.2
latest version: 4.5.4
Please update conda by running
$ conda update -n base conda
# …