importing module relative to current script (beyond top level)

Question

I have a project a with several versions of main#.py so I organize them into a directory called run. I normally run project a from ./a by calling python run/main1.py. Because main1.py involves imports beyond the top level package, I need to specify sys.path.insert(0, "./") in main1.py.

Now I've created project b which imports main1.py from a. From b\main.py, how do I get main1.py to import a/utils.py specifically?

Requirements:

1. Project a is a project I worked on long ago so I would like to make limited changes to just its headers. I would like python run/main1.py to work like it currently does.

2. I may move the projects between different computers so main1.py needs to import utils.py relative to itself. (ie. not importing with absolute path)

3. I would like the solution to be scalable. b will need to import modules from several other projects structured like a. I feel that expanding the system's PATH variable may just mess things up. Is there a neater solution?

My projects' files are as follows:

• a
  • run
    • main1.py
  • utils.py
• b
  • main.py
  • utils.py

in a/run/main1.py:

import sys
sys.path.insert(0, "./")
from utils import hello    # Anyway to specify this to be ../utils.py ?
hello()

in a/utils.py:

def hello():
    print('hello from a')

in b/main.py:

import sys
sys.path.append("../")
from a.run import main1

import utils
utils.hello()

in b/utils.py:

def hello():
    print('hello from b')

This is the current result. I would like the first line to print 'hello from a':

>>> python run/main1.py:
hello from a
>>> cd ../b
>>> python run/main.py:
hello from b           (we want this to be "hello from a")
hello from b