def transfer_annotations_prob(mapping_matrix, to_transfer):
    """
    Transfer cell annotations onto space through a mapping matrix.
    Args:
        mapping_matrix (ndarray): Mapping matrix with shape (number_cells, number_spots).
        to_transfer (ndarray): Cell annotations matrix with shape (number_cells, number_annotations).
    Returns:
        A matrix of annotations onto space, with shape (number_spots, number_annotations)
    """
    return mapping_matrix.transpose() @ to_transfer