docs: def encode(self, sequence):
          """ Encodes a ``sequence``.
  
          Args:
              sequence (str): String ``sequence`` to encode.
  
          Returns:
              torch.Tensor: Encoding of the ``sequence``.
          """
          sequence = super().encode(sequence)
          sequence = self.tokenize(sequence)
          vector = [self.stoi.get(token, self.unknown_index) for token in sequence]
          if self.append_eos:
              vector.append(self.eos_index)
          return torch.tensor(vector)