Deprecated since 3.12, removed in 3.17. The ByteString ABC has been deprecated. Use isinstance(obj, collections.abc.Buffer) to test if obj implements the buffer protocol at runtime. For use in type annotations, either use Buffer or a union that explicitly specifies the types your code supports (e.g., bytes | bytearray | memoryview). ByteString was originally intended to be an abstract class that would serve as a supertype of both bytes and bytearray. However, since the ABC never had any methods, knowing that an object was an instance of ByteString never actually told you anything useful about the object. Other common buffer types such as memoryview were also never understood as subtypes of ByteString (either at runtime or by static type checkers). See PEP 688 for more details.
All the operations on a read-write sequence.
Concrete subclasses must provide __new__ or __init__,
__getitem__, __setitem__, __delitem__, __len__, and insert().