def unix_device(self, prefix: Optional[str] = None) -> str:
        """Generate a Unix device file name.

        If ``prefix`` is ``None``, a random prefix will be used. The list of
        valid prefixes include: ``'sd'``, ``'vd'``, and ``'xvd'``.

        :sample:
        :sample: prefix='mmcblk'
        """
        if prefix is None:
            prefix = self.random_element(self.unix_device_prefixes)
        suffix: str = self.random_element(string.ascii_lowercase)
        path = f"/dev/{prefix}{suffix}"
        return path
Generate a Unix device file name.

        If ``prefix`` is ``None``, a random prefix will be used. The list of
        valid prefixes include: ``'sd'``, ``'vd'``, and ``'xvd'``.

        :sample:
        :sample: prefix='mmcblk'
        
faker/providers/file/__init__.py