Encodes a ``sequence``.

        Args:
            sequence (str): String ``sequence`` to encode.

        Returns:
            torch.Tensor: Encoding of the ``sequence``.

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)