supporting both str and bytes on write file

[DeaD_EyE]

There are many ways to do this.

class ReadWriteMixed:
    def __init__(self, fileobj):
        self.fileobj = fileobj
    
    def __getattr__(self, name):
        """
        For lazyness
        """
        return getattr(self.fileobj, name)

    def write(self, data: str | bytes):
        if isinstance(data, str) and "b" in self.fileobj.mode:
            data = data.encode()
        elif isinstance(data, bytes) and "b" not in self.fileobj.mode:
            data = data.decode()

        self.fileobj.write(data)

    def read_bytes(self, size=None):
        data = self.fileobj.read(size)
        if "b" not in self.fileobj.mode:
            data = data.encode()
        return data

    def read_text(self, size=None):
        data = self.fileobj.read(size)
        if "b" in self.fileobj.mode:
            data = data.decode()
        return data

def open_mixed(file, mode="r"):
    return ReadWriteMixed(open(file, mode))


file_like = open_mixed("/etc/issue", "rb") # open in bytes mode
print(file_like.read_text())  # read_text makes an implicit conversion, if mode is bytes

But I would never use this code. The problem is, that you have lesser control if something happens automagically.