Ultralytics Code Refactor https://ultralytics.com/actions (#13152)

Refactor code for speed and clarity

utils/general.py

@@ -343,7 +343,7 @@ def check_online():
     import socket
 
     def run_once():
-        # Check once
+        """Checks internet connectivity by attempting to create a connection to "1.1.1.1" on port 443."""
         try:
             socket.create_connection(("1.1.1.1", 443), 5)  # check host accessibility
             return True
@@ -587,7 +587,7 @@ def check_amp(model):
     from models.common import AutoShape, DetectMultiBackend
 
     def amp_allclose(model, im):
-        # All close FP32 vs AMP results
+        """Compares FP32 and AMP model inference outputs, ensuring they are close within a 10% absolute tolerance."""
         m = AutoShape(model, verbose=False)  # model
         a = m(im).xywhn[0]  # FP32 inference
         m.amp = True
@@ -652,7 +652,7 @@ def download(url, dir=".", unzip=True, delete=True, curl=False, threads=1, retry
     """Downloads and optionally unzips files concurrently, supporting retries and curl fallback."""
 
     def download_one(url, dir):
-        # Download 1 file
+        """Downloads a single file from `url` to `dir`, with retry support and optional curl fallback."""
         success = True
         if os.path.isfile(url):
             f = Path(url)  # filename