diff --git a/pyrogram/file_id.py b/pyrogram/file_id.py
index 95f6ccbf..1a54a49d 100644
--- a/pyrogram/file_id.py
+++ b/pyrogram/file_id.py
@@ -21,6 +21,7 @@ import logging
 import struct
 from enum import IntEnum
 from io import BytesIO
+from typing import List
 
 from pyrogram.raw.core import Bytes, String
 
@@ -63,7 +64,7 @@ def rle_encode(s: bytes) -> bytes:
     Returns:
         ``bytes``: The encoded bytes
     """
-    r: bytes = b""
+    r: List[int] = []
     n: int = 0
 
     for b in s:
@@ -71,15 +72,15 @@ def rle_encode(s: bytes) -> bytes:
             n += 1
         else:
             if n:
-                r += bytes([0, n])
+                r.extend((0, n))
                 n = 0
 
-            r += bytes([b])
+            r.append(b)
 
     if n:
-        r += bytes([0, n])
+        r.extend((0, n))
 
-    return r
+    return bytes(r)
 
 
 def rle_decode(s: bytes) -> bytes:
@@ -87,12 +88,12 @@ def rle_decode(s: bytes) -> bytes:
 
     Parameters:
         s (``bytes``):
-            Bytes to encode
+            Bytes to decode
 
     Returns:
-        ``bytes``: The encoded bytes
+        ``bytes``: The decoded bytes
     """
-    r: bytes = b""
+    r: List[int] = []
     z: bool = False
 
     for b in s:
@@ -101,12 +102,12 @@ def rle_decode(s: bytes) -> bytes:
             continue
 
         if z:
-            r += b"\x00" * b
+            r.extend((0,) * b)
             z = False
         else:
-            r += bytes([b])
+            r.append(b)
 
-    return r
+    return bytes(r)
 
 
 class FileType(IntEnum):