Recommends items for a user

        Calculates the N best recommendations for a user, and returns a list of itemids, score.

        Parameters
        ----------
        userid : int
            The userid to calculate recommendations for
        user_items : csr_matrix
            A sparse matrix of shape (number_users, number_items). This lets us look
            up the liked items and their weights for the user. This is used to filter out
            items that have already been liked from the output, and to also potentially
            calculate the best items for this user.
        N : int, optional
            The number of results to return
        filter_items : sequence of ints, optional
            List of extra item ids to filter out from the output
        recalculate_user : bool, optional
            When true, don't rely on stored user state and instead recalculate from the
            passed in user_items

        Returns
        -------
        list
            List of (itemid, score) tuples

def recommend(self, userid, user_items,
                  N=10, filter_already_liked_items=True, filter_items=None, recalculate_user=False):
        """
        Recommends items for a user

        Calculates the N best recommendations for a user, and returns a list of itemids, score.

        Parameters
        ----------
        userid : int
            The userid to calculate recommendations for
        user_items : csr_matrix
            A sparse matrix of shape (number_users, number_items). This lets us look
            up the liked items and their weights for the user. This is used to filter out
            items that have already been liked from the output, and to also potentially
            calculate the best items for this user.
        N : int, optional
            The number of results to return
        filter_items : sequence of ints, optional
            List of extra item ids to filter out from the output
        recalculate_user : bool, optional
            When true, don't rely on stored user state and instead recalculate from the
            passed in user_items

        Returns
        -------
        list
            List of (itemid, score) tuples
        """
        pass