def get_base_score(df, ctl_genes):
    """Get LFC of each guide when paired with controls

    Parameters
    ----------
    df: DataFrame
        Anchor guides paired with all of their target guides. Has columns "anchor_guide" and "lfc"
    ctl_genes: list
        Control genes

    Returns
    -------
    DataFrame
        Median LFC for each anchor guide
    """
    base_score = (df[df.target_gene.isin(ctl_genes)]
                  .groupby(['anchor_guide', 'condition'])
                  .agg({'lfc': 'median'})
                  .reset_index())
    return base_score