squashed commit of many breaking changes

Dropping Support for Python 3.7; adding support for Python 3.9

NetUtils.py

@@ -1,33 +1,34 @@
 from __future__ import annotations
 import asyncio
-import json
 import logging
 import typing
+from json import loads, dumps
 
 import websockets
 
-
 class Node:
     endpoints: typing.List
+    dumper = staticmethod(dumps)
+    loader = staticmethod(loads)
 
     def __init__(self):
         self.endpoints = []
 
     def broadcast_all(self, msgs):
-        msgs = json.dumps(msgs)
+        msgs = self.dumper(msgs)
         for endpoint in self.endpoints:
-            asyncio.create_task(self.send_json_msgs(endpoint, msgs))
+            asyncio.create_task(self.send_encoded_msgs(endpoint, msgs))
 
     async def send_msgs(self, endpoint: Endpoint, msgs):
         if not endpoint.socket or not endpoint.socket.open or endpoint.socket.closed:
             return
         try:
-            await endpoint.socket.send(json.dumps(msgs))
+            await endpoint.socket.send(self.dumper(msgs))
         except websockets.ConnectionClosed:
             logging.exception("Exception during send_msgs")
             await self.disconnect(endpoint)
 
-    async def send_json_msgs(self, endpoint: Endpoint, msg: str):
+    async def send_encoded_msgs(self, endpoint: Endpoint, msg: str):
         if not endpoint.socket or not endpoint.socket.open or endpoint.socket.closed:
             return
         try: