import packages not work python 3 -

i create packages in python 3 , went try import in main folder not work

my architecture

--mainfolder   --__init__.py   --start.py   --packages     --__init__.py     --file1.py     --file2.py 

when start programme console this

python3 start.py 

i have error

    traceback (most recent call last):   file "start.py", line 8, in <module>     packages import class1 importerror: cannot import name 'class1' 

my fist init file in mainfolder empty

in init in packages try

1 from .file1 import class1

2 from . import class1

3 from . import file1

in start.py try call module in many ways

1 from packages import class1

2from .packages import class1

3from . import class1

edit

in packages/file1 code this

import time import sys  class class1(objet):    def run(self):       print('test') 

in call file in start.py this

class1().run() 

i try how import module sub directory

this cannot import modules in python3 sub directory

and importing module sub-directory works in python 2, not python 3

i think file init not load because went add

sys.path.append('path/to/my/package') 

in import packages work pycharm give me , error each time , not compile script

as @john gordon said:

if class1 in file1.py can import with

from packages.file1 import class1 

you can import class1 packages/init.py with

from file1 import class1 

then import straight packages

from packages import class1