code: def is_sonorus(self):
          
          if not self.is_consonant():
              return False
          if self.letter in self.forever_sonorus:
              return True
          if self.letter in self.forever_deaf:
              return False
          if self.__forsed_sonorus:
              return True
          if self.__forsed_sonorus is False:
              return False
          for son, _ in self.sonorus_deaf_pairs:
              if self.letter == son:
                  return True
          return False
docs: Звонкая ли согласная.