def fit(self, x_train_vects: Tuple[Union[csr_matrix, List]], y_train: Tuple[str]) -> None:
        """Train classifier

        Parameters:
            x_train_vects: vectorized question for train dataset
            y_train: answers for train dataset

        Returns:
            None
        """
        if isinstance(x_train_vects, tuple):
            if len(x_train_vects) != 0:
                if isinstance(x_train_vects[0], csr_matrix):
                    self.x_train_features = vstack(list(x_train_vects))
                elif isinstance(x_train_vects[0], np.ndarray):
                    self.x_train_features = np.vstack(list(x_train_vects))
                else:
                    raise NotImplementedError('Not implemented this type of vectors')
            else:
                raise ValueError("Train vectors can't be empty")
        else:
            self.x_train_features = x_train_vects

        self.y_train = list(y_train)
Train classifier

        Parameters:
            x_train_vects: vectorized question for train dataset
            y_train: answers for train dataset

        Returns:
            None
        
deeppavlov/models/classifiers/cos_sim_classifier.py