':param FilePath requested: The requested device name.
:param discovered: A ``FilePath`` giving the path of the device which
was discovered on the system or ``None`` if no new device was
discovered at all.'

def __init__(self, requested, discovered):

    if (not isinstance(requested, FilePath)):
        raise TypeError('requested    must    be    FilePath,    not    {}'.format(type(requested)))
    if (not isinstance(discovered, (FilePath, NoneType))):
        raise TypeError('discovered    must    be    None    or    FilePath,    not    {}'.format(type(discovered)))
    self.requested = requested
    self.discovered = discovered
