def get_annotated_lfcs(lfcs, annotations, merge_on=None, lfc_merge_on=None, annotation_merge_on=None):
    """Merge lfcs and annotatsion

    lfcs: dataframe, log-fold changes
    annotations: dataframe, sgRNA annotations
    merge_on: str or None, name of sgRNA column to merge on. Must be present in both
        lfc and annotation dataframes if supplied,
        otherwise supply unique merge column to each |
    lfc_merge_on: str or None, name of sgRNA column to merge on |
    annotation_merge_on: str or None, name of sgRNA column to merge on
    """
    annotated_lfcs = lfcs.merge(annotations, how='inner', on=merge_on, left_on=lfc_merge_on, right_on=annotation_merge_on)
    return annotated_lfcs