chore: improve rhci_progress typing, remove mutable arguments

freqtrade/util/rich_progress.py

@@ -1,13 +1,20 @@
-from typing import Callable, List, Union
+from typing import Callable, List, Optional, Union
 
 from rich.console import ConsoleRenderable, Group, RichCast
 from rich.progress import Progress
 
 
 class CustomProgress(Progress):
-    def __init__(self, *args, cust_objs=[], cust_callables: List[Callable] = [], **kwargs) -> None:
-        self._cust_objs = cust_objs
-        self._cust_callables = cust_callables
+    def __init__(
+        self,
+        *args,
+        cust_objs: Optional[List[ConsoleRenderable]] = None,
+        cust_callables: Optional[List[Callable[[], ConsoleRenderable]]] = None,
+        **kwargs,
+    ) -> None:
+        self._cust_objs = cust_objs or []
+        self._cust_callables = cust_callables or []
+
         super().__init__(*args, **kwargs)
 
     def get_renderable(self) -> Union[ConsoleRenderable, RichCast, str]: