def get_len_of_bedtool(bed_obj, cov_col=3, cutoff=1):
    """
    Get the number of rows (sites) of BedTool object
    :param bed_obj:
    :param cutoff:
    :return:
    """
    # covList = []
    # for row in bed_obj:
    #     covList.append(int(row[cov_col]))
    # covSeries = pd.Series(covList)
    df = bed_obj.to_dataframe()
    return (df.iloc[:, cov_col] >= cutoff).sum()