def resolve_sound(self, string):
     if isinstance(string, Sound):  # noqa: F405
         return self.features[string.featureset]
     if set(string.split(' ')).intersection(
             list(self.sound_classes) + ['diphthong', 'cluster']):
         return self._from_name(string)
     string = nfd(string)
     return self._parse(string)
 def normalize(self, string):
     """Normalize the string according to normalization list"""
     return ''.join([self._normalize.get(x, x) for x in nfd(string)])