setuptools find_packages returns empty list

When I try to install my package, it doesn't install anything. When I execute find_packages manually, it returns an empty list.

Here is my setup.py file:

from setuptools import setup, find_packages

with open('README.md') as f:
    long_description = f.read()

setup(
    ...

    packages=find_packages(),
    python_requires='>=3.6',

    ...
)

My directory structure is

hackathon-base
|- hackathon
   |- __main__.py
   |- dir1
   |- dir2
|- setup.py