'Check whether it\'s possible to import the necessary modules.
There is no check on the file formats at runtime.
:raises :exc:`ReplayGainError`: if the modules cannot be imported'

def _import_audiotools(self):

    try:
        import audiotools
        import audiotools.replaygain
    except ImportError:
        raise FatalReplayGainError(u'Failed    to    load    audiotools:    audiotools    not    found')
    self._mod_audiotools = audiotools
    self._mod_replaygain = audiotools.replaygain
