diff --git a/main.py b/main.py
index ebfee43..c3b7225 100644
--- a/main.py
+++ b/main.py
@@ -9,12 +9,12 @@ from pathlib import Path
 
 import config
 import util
-#import bot
-#import logic
 
 from new_bot import MatrixBot
 from bot_types import MatrixBotConfig
 
+import nio.events
+
 from datatypes import AppConfig
 
 async def main() -> None:
@@ -42,6 +42,7 @@ async def main() -> None:
         storage_directory=Path(cfg.store_dir)
     )
     bot = MatrixBot(matrix_bot_config)
+    bot.add_event_callback(None, nio.events.Event)
 
     # start the app
     bot.start()
diff --git a/new_bot.py b/new_bot.py
index 66dffc8..fc89fbd 100644
--- a/new_bot.py
+++ b/new_bot.py
@@ -8,11 +8,13 @@ import json
 import os
 import re
 from urllib.parse import urlparse
-from typing import Any
+from typing import Any, Callable, Awaitable
 
 from nio import AsyncClient, AsyncClientConfig, SyncResponse
 from nio import LoginResponse, LoginError, WhoamiResponse, WhoamiError
 
+import nio.events
+
 from bot_types import *
 
 
@@ -128,6 +130,18 @@ class MatrixBot:
             return os.environ["MATRIX_PASSWORD"]
         print("--- A password is required (btw you might use MATRIX_PASSWORD envvar) ---")
         return await aioconsole.ainput("Password: ")
+
+    @staticmethod
+    async def _debug_event_callback(*args, **kwargs) -> None:
+        """Just prints types of arguments"""
+        try:
+            print(f"_debug_event_callback ({len(args)} args, {len(kwargs)} kwargs)")
+            for a in args:
+                print(f"  - {type(a)}")
+            for k in kwargs:
+                print(f"  * {k} = {kwargs[k]}")
+        except:
+            traceback.print_exc()
     
 
     async def _write_next_batch(self, next_batch: str) -> None:
@@ -286,8 +300,6 @@ class MatrixBot:
         # we should stop when this task stops
         self._logger.debug("_background_coroutine is started")
         stop_wait_task = asyncio.create_task(self._stop_event.wait())
-        self._client = self._build_client(self._config)
-        self._setup_client_callbacks()
         # perform login
         login_task = asyncio.create_task(self._client_login())
         try:
@@ -324,14 +336,16 @@ class MatrixBot:
         # check if config is valid
         self._validate_bot_config(config) # may raise an Exception
         # save the config
-        self._config = config
+        self._config: MatrixBotConfig = config
         # create the logger
         self._logger = logging.getLogger(self._build_matrix_username(config))
         self._logger.setLevel(logging.DEBUG)
+        # create the client
+        self._client: AsyncClient = self._build_client(self._config)
+        self._setup_client_callbacks()
 
         # prepare some private data
         self._background_task: asyncio.Task | None = None
-        self._client: AsyncClient = None # type: ignore
         self._last_next_batch_dump: float = 0.0
         self._last_next_batch: str | None = None
         self._cb_password = self._default_password_callback
@@ -360,4 +374,11 @@ class MatrixBot:
         except:
             traceback.print_exc()
         self._stop_event = None
-        self._background_task = None
\ No newline at end of file
+        self._background_task = None
+
+    def add_event_callback(self, callback: Callable[[Any], Awaitable[None]] | None, event_class: nio.events.Event) -> None:
+        """Added event callback for events of specified class.
+            Use `None` instead of callback to print parameter types you need to use in your callback."""
+        if callback is None:
+            callback = self._debug_event_callback
+        self._client.add_event_callback(callback, event_class) # type: ignore
\ No newline at end of file