fix packaging

remove hatchling depenency for simplicity
downgrade python version to a more common one
use numpy as demonstration

pyproject.toml

-[build-system]
-requires = ["hatchling", "hatch-requirements-txt"]
-build-backend = "hatchling.build"
-
 [project]
+# basic information
 name = "your_project_name"
-readme = "README.md"
-requires-python = ">=3.11"
 description = "A description of your awesome Python project"
+authors = [
+  {name = "Your Name", email = "example@email.xyz"},
+]
+
 # This is the version of your project. You can increase the counter to indicate changes
 version = "0.1.0"
-dynamic = ["dependencies"]
 
+# it is nice to pin down the version used to develop the project
+requires-python = ">=3.9"
 
-[tool.hatch.metadata.hooks.requirements_txt]
-files = ["requirements.txt"]
-
-# This is where you tell the installer where your code lives
-pythonpath = [
-  "your_project_name"
-]
-
+readme = "README.md"

your_project_name/main.py → your_project_name/__main__.py

@@ -11,7 +11,7 @@ Please refer to the LICENSE located in the root of this repository.
 import sys
 
 # then by third party
-# e.g. import numpy as np
+import numpy as np
 
 # then by your own code
 from your_project_name.module1.funct_say_hello import say_hello
@@ -24,3 +24,12 @@ if __name__ == "__main__":
     say_hello(file_name)
 
     another_function()
+
+    small_array = np.zeros((2, 2))
+
+    small_array[0, 0] = 1
+    small_array[0, 1] = 2
+    small_array[1, 0] = 3
+    small_array[1, 1] = 4
+
+    print(small_array)