stick with bytearray, see #247

Author: abebus

w3lib/http.py

@@ -100,21 +100,21 @@ def headers_dict_to_raw(headers_dict: HeadersDictInput | None) -> bytes | None:
     if not headers_dict:
         return b""
 
-    parts = b""
+    parts = bytearray()
 
     for key, value in headers_dict.items():
         if isinstance(value, bytes):
             if parts:
-                parts += b"\r\n"
-            parts += key + b": " + value
+                parts.extend(b"\r\n")
+            parts.extend(key + b": " + value)
 
         elif isinstance(value, (list, tuple)):
             for v in value:
                 if parts:
-                    parts += b"\r\n"
-                parts += key + b": " + v
+                    parts.extend(b"\r\n")
+                parts.extend(key + b": " + v)
 
-    return parts
+    return bytes(parts)
 
 
 def basic_auth_header(