Values from outside of your application
Connecting to a database
Determining the operating system
Setting which need to change
Sensitive data
Reading an environmentaal variable
import os
os_version = os.getenv('OS')
print(os_version)
Using dotenv
Store environmental variables in text file
# .env file
DATAbase = Sample_Connection_string
#app.py
from dotenv import load_dotenv
import os
load_dotenv()
database = os.getenv('DATAbase')
print(database)
插入一个中文理解（转载自知乎用户【大大的甜甜圈】）：
PS： 用 dotenv 就不用在各个文件中引入配置文件，保护敏感信息，利于后期代码维护。
