Add todo and docstring about the main file.

Clear unused variable.

main.py

@@ -3,10 +3,13 @@ import pathlib
 import json
 import docker
 
+# TODO Update readme file badge with blender version
+# TODO add a check if the image build are stored in the docker register
+
 
 def get_data_from_json() -> (str, str):
+    """From the json file, get blender version (major and minor), and return this information."""
     file = pathlib.Path(os.getcwd(), 'build.json')
-    data: dict = {}
 
     with open(file, 'r') as f:
         data = json.load(f)
@@ -20,6 +23,10 @@ def get_data_from_json() -> (str, str):
 
 
 def build_docker(b3d_version: (str, str), latest: bool = False):
+    """
+    Generate docker image, request the blender version (major, minor) with the keyword b3d_version, and can be
+    tagged with latest or only blender version info.
+    """
     client = docker.from_env()
     if os.environ.get('docker_hub_password'):
         client.login(username=os.environ['docker_hub_user'], password=os.environ['docker_hub_password'])