一. 兩個概念：

1.module

A module is a file containing Python definitions and statements. 

2.package

Packages are a way of structuring Python’s module namespace by using “dotted module names”
……
The __init__.py files are required to make Python treat the directories as containing packages; 
……
 

二. import和from import的用法

import package1  #✅
import module  #✅
from module import function  #✅
from package1 import module  #✅
from package1.package2 import  #✅
import module.function1  #❌ 

import X :

imports the module X
 
,and creates a reference to that module in the current
namespace.Then you need to define completed module path to access a
particular attribute or method from inside the module.

from X import * :

*imports the module X,and creates references to all public objects
   defined by that module in the current namespace 
 
(that is, everything
   that doesn’t have a name starting with“_”)or what ever the name
   you mentioned.Orin other words, after you’ve run this statement, you can simply
   use a plain name to refer to things defined in module X.But X itself
   isnot defined, so X.name doesn’t work.Andif name was already
   defined, it is replaced by the new version.Andif name in X is
   changed to point to some other object, your module won’t notice.*This makes all names from the module available in the local namespace.