feature: added a new type amalgamating the return types of the 'open' BIF

custtypes.py

@@ -7,9 +7,11 @@ from typing import Required
 from collections.abc import Sequence
 from pathlib import Path, PurePath, PurePosixPath, PureWindowsPath, PosixPath, WindowsPath
 from enum import StrEnum, auto
+from io import TextIOBase, BufferedIOBase, RawIOBase
 
 ExecutedPath: Neotype = PosixPath | WindowsPath
 IdlePath: Neotype = PurePosixPath | PureWindowsPath
+File: Neotype = TextIOBase | BufferedIOBase | RawIOBase
 
 class RootFate(StrEnum):
     disposal = auto()