It would be useful to have a shared API for consuming bytes and bytearrays.

At present, I need to write very similar code twice. Some existing codebases only support bytes (perhaps forgetting bytearrays exist). Adding support for bytearray would be trivial if there was a shared API.

These are the functions/macros that can have "BytesOrByteArray" equivalents:
* PyBytes_Check
* PyBytes_CheckExact
* PyBytes_Size
* PyBytes_GET_SIZE
* PyBytes_AsString
* PyBytes_AS_STRING
* PyBytes_AsStringAndSize

Here are some example implementations for the macros:

#define PyBytesOrByteArray_Check(ob) (PyBytes_Check(ob) || PyByteArray_Check(ob))
#define PyBytesOrByteArray_AS_STRING(ob) (PyBytes_Check(ob) ? PyBytes_AS_STRING(ob) : PyByteArray_AS_STRING(ob))
#define PyBytesOrByteArray_GET_SIZE(ob) #define PyByteArray_GET_SIZE(self) (assert(PyBytesOrByteArray_Check(self)), Py_SIZE(self))