title: ModuleNotFoundError, why I am getting this?
body: <p>I have the follow repository structure:</p>
  
  <pre><code>main_repo/
  ├── __init__.py
  ├── README.md
  ├── requirements.txt
  ├── setup.py
  ├── mod0
  │   ├── code_0.py
  │   ├── __init__.py
  │ 
  ├── test
  │   ├── __init__.py
  │   └── test_m1.py
  ├── module1
  │   ├── __init__.py
  │   ├── m1.py
  │   ├── m2.py
  │   ├── m3.py
  </code></pre>
  
  <p>I have a little setup.py file with the following code</p>
  
  <pre><code>import os
  import sys
  
  if sys.argv[-1] == 'run1':
      os.system('python3 test/test_m1.py')
      sys.exit()
  </code></pre>
  
  <p>As you can see, I just want to execute <code>python3 setup.py run1</code> to execute my <code>test_m1.py</code> file. But I have a <code>ModuleNotFoundError</code>, and I don't know why since I have a <code>__init__.py</code> file in every repo.</p>
  
  <p>Additionnally, the import I used on the file I want to test is in the form of <code>from module1.m1 import *</code>. The output error is <code>ModuleNotFoundError: no module named module1</code>.</p>
  
  <p>Do I need to add something else to get the import done correctly?</p>