def get_no_control_guides(df, guide_base_score):
    """Get guides that are not paired with controls

    Parameters
    ----------
    df: DataFrame
        DataFrame with the column anchor_gene
    guide_base_score: DataFrame
        Guide scores when paired with controls

    Returns
    -------
    list
        Guides without control pairs
    """
    starting_guides = set(df.anchor_guide.to_list())
    base_score_guides = set(guide_base_score.anchor_guide.to_list())
    no_control_guides = list(starting_guides - base_score_guides)
    return no_control_guides