docs: add docstring to 'fetch'

1 files changed, 10 insertions, 0 deletions

diff --git a/main.py b/main.py
index e1c6273..000a962 100644
--- a/main.py
+++ b/main.py
@@ -34,6 +34,16 @@ def get_urls(filename: str, limit: int | None = None) -> list[str]:
 
 
 async def fetch(session: aiohttp.ClientSession, url: str, semaphore: asyncio.Semaphore) -> str:
+    """Fetch a URL under the given SESSION.
+
+    Use SEMAPHORE to limit the number of tasks that can make an HTTP
+    request at at time.
+
+    This function is the atomic task that executes concurrently with
+    its brethren to ping various websites.
+
+    """
+
     try:
         async with semaphore, session.get(url) as response:
             print(".", end="", flush=True)