Delete unnecessary lines

pytchat/tool/dlworker.py

@@ -1,23 +1,37 @@
 from . import parser
 
 class DownloadWorker:
+    """
+    DownloadWorker : associates a download session with a block.
+
+    Parameter
+    ----------
+    fetch : func
+        download function of asyncdl
+
+    block : Block
+        chunk of chat_data
+    """
     def __init__(self, fetch, block):
         self.block = block
         self.fetch = fetch
         
-    async def run(self,session):
+    async def run(self, session):
+        """Remove extra chats just after ready_blocks(). """
         temp_last = self.block.temp_last
         self.block.chat_data, continuation = self.cut(
             self.block.chat_data, 
             self.block.continuation, 
             self.block.last,
             temp_last )
+        """download loop """
         while continuation:
             data, cont, fetched_last = await self.fetch(continuation, session)
             data, continuation = self.cut(data, cont, fetched_last, temp_last)
             self.block.chat_data.extend(data)
         
     def cut(self, data, cont, fetched_last, temp_last):
+        """Remove extra chats."""
         if fetched_last < temp_last or temp_last == -1:
             return data, cont
         for i, line in enumerate(data):