Return similar words based on a metric

        Parameters
        ----------
        word : string
        n : int (default 10)

        Returns
        -------
        Tuple of 2 numpy.array:
            1. position in self.vocab
            2. cosine similarity

def similar(self, word, n=10, metric="cosine"):
        """
        Return similar words based on a metric

        Parameters
        ----------
        word : string
        n : int (default 10)

        Returns
        -------
        Tuple of 2 numpy.array:
            1. position in self.vocab
            2. cosine similarity
        """
        return self.closest(self[word], n=n, metric=metric)