python-3.x – 在python3中使用importlib进行动态导入时出错

目录结构

main.py

#Note: I will only modify line 4 that uses importlib
import importlib
if __name__ == '__main__':
    print("In main.py")
    hello = importlib.import_module('hello',package='./')
    print("Loaded hello.py")
    hello.hello()

hello.py

def hello():
    print('Hello world')

文件夹/ hello.py

def hello():
    print('Hello world in folder')

意见

如果我做

hello = importlib.import_module(‘hello’,package =’./’)或

hello = importlib.import_module(‘hello’)

它从根文件夹导入hello.py并打印hello world.

如果我做

hello = importlib.import_module(‘folder.hello’)

它从根文件夹导入文件夹/ hello.py并在文件夹中打印hello world.

但如果我这样做

hello = importlib.import_module(‘hello’,package =’folder’)或

hello = importlib.import_module(‘hello’,package =’./ folder’)

它给出了错误

Traceback (most recent call last):
  File "main.py",line 4,in <module>
    hello = importlib.import_module('hello',package='./folder')
  File "/usr/lib/python3.6/importlib/__init__.py",line 126,in import_module
    return _bootstrap._gcd_import(name[level:],package,level)
  File "<frozen importlib._bootstrap>",line 994,in _gcd_import
  File "<frozen importlib._bootstrap>",line 971,in _find_and_load
  File "<frozen importlib._bootstrap>",line 953,in _find_and_load_unlocked
ModuleNotFoundError: No module named 'hello'

问题

我不确定这里发生了什么.我很确定我对python模块和包的理解有问题.有人可以解释为什么这是预期的行为？