Fix automating build workflow for Python

.github/workflows/python.yml

@@ -32,7 +32,6 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           pip install black
-          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
       - name: Lint with black
         run: |
           black codes/python

codes/python/build.py

@@ -1,17 +1,20 @@
 import glob
 import py_compile as pyc
 
-src_paths = sorted(glob.glob("codes/python/**/*.py"))
-num_src = len(src_paths)
-num_src_error = 0
+if __name__ == "__main__":
+    # find source code files
+    src_paths = sorted(glob.glob("codes/python/**/*.py"))
+    num_src = len(src_paths)
+    num_src_error = 0
 
-for src_path in src_paths:
-    try:
-        pyc.compile(src_path, doraise=True)
-    except pyc.PyCompileError as e:
-        num_src_error += 1
-        print(e)
+    # compile python code
+    for src_path in src_paths:
+        try:
+            pyc.compile(src_path, doraise=True)
+        except pyc.PyCompileError as e:
+            num_src_error += 1
+            print(e)
 
-print(f"===== Build Summary =====")
-print(f"Total: {num_src}")
-print(f"Error: {num_src - num_src_error}")
+    print(f"===== Build Complete =====")
+    print(f"Total: {num_src}")
+    print(f"Error: {num_src_error}")