Importing main.py into another module (contained in the same directory)

Question

How do I import a class from main.py into another file in the same directory?

File structure:

Project
    |-- main.py
    |-- first_file.py
    |-- second_file.py

main.py :

class ClassX():
    def random1(self):
        ....
        return stuff

    def get(self):
        class_x_stuff = self.random1()
        print class_x_stuff

app = webapp2.WSGIApplication([
    ('/classw', ClassW),
    ('/classx', ClassX)
], debug=True)

first_file.py :

import main

checkpoint = main.ClassX()
print checkout

Output:

AttributeError: 'module' object has no attribute 'ClassX'

Resources I've used:

1. How to import the class within the same directory or sub directory?
2. AttributeError: 'module' object has no attribute

I'm able to import the first_file.py into main.py as well as into second_file.py . But I am unable to import main.py into the other files.

Renaming the main.py file, (for example, proj_main.py ) results in an error:

Traceback (most recent call last):
File "/usr/local/google_appengine/google/appengine/runtime/wsgi.py", line 240, in Handle
  handler = _config_handle.add_wsgi_middleware(self._LoadHandler())
File "/usr/local/google_appengine/google/appengine/runtime/wsgi.py", line 299, in _LoadHandler
  handler, path, err = LoadObject(self._handler)
File "/usr/local/google_appengine/google/appengine/runtime/wsgi.py", line 85, in LoadObject
  obj = __import__(path[0])

ImportError: No module named main

What are my options? How can I resolve this issue?

EDIT:

Full Traceback:

INFO     2017-10-02 22:10:21,744 dispatcher.py:226] Starting module "default" running at: http://localhost:7070
INFO     2017-10-02 22:10:21,747 admin_server.py:116] Starting admin server at: http://localhost:8000
ERROR    2017-10-02 22:10:24,017 wsgi.py:263] 
Traceback (most recent call last):
  File "/usr/local/google_appengine/google/appengine/runtime/wsgi.py", line 240, in Handle
handler = _config_handle.add_wsgi_middleware(self._LoadHandler())
  File "/usr/local/google_appengine/google/appengine/runtime/wsgi.py", line 299, in _LoadHandler
handler, path, err = LoadObject(self._handler)
  File "/usr/local/google_appengine/google/appengine/runtime/wsgi.py", line 85, in LoadObject
obj = __import__(path[0])
  File "/Users/mycomputer/Documents/project_folder/main.py", line 34, in <module>
from first_file import ClassY
  File "/Users/mycomputer/Documents/project_folder/first_file.py", line 20, in <module>
    checkpoint = main.ClassX()
AttributeError: 'module' object has no attribute ‘ClassX’
INFO     2017-10-02 22:10:24,023 module.py:832] default: "GET / HTTP/1.1" 500 -

Answer 1

The problem is that I was experiencing circular dependency :

File "/Users/mycomputer/Documents/project_folder/main.py", line 34, in <module>
from first_file import ClassY

Note that main.py was importing from first_file and then first_file was importing from main.py which caused a circular import gotcha .

Solution:

first_file.py

import second_file

checkpoint = second_file.class_x()
    print checkout

second_file.py

import main

def class_x():
    item = main.ClassX()
    return item