Add default None for maxlen at xtrim command (#2188)

* Add default None for maxlen at xtrim command

* Fix linter

Co-authored-by: Mikhail Fedorov <mfgnik@yandex.team.ru>
Co-authored-by: dvora-h <67596500+dvora-h@users.noreply.github.com>

redis/commands/core.py

@@ -3842,7 +3842,7 @@ def xrevrange(
     def xtrim(
         self,
         name: KeyT,
-        maxlen: Union[int, None],
+        maxlen: Union[int, None] = None,
         approximate: bool = True,
         minid: Union[StreamIdT, None] = None,
         limit: Union[int, None] = None,
@@ -3863,6 +3863,9 @@ def xtrim(
         if maxlen is not None and minid is not None:
             raise DataError("Only one of ``maxlen`` or ``minid`` " "may be specified")
 
+        if maxlen is None and minid is None:
+            raise DataError("One of ``maxlen`` or ``minid`` must be specified")
+
         if maxlen is not None:
             pieces.append(b"MAXLEN")
         if minid is not None: