def left_align_report(row):
    """Gets and formats info from left-aligned indel
    
    Args:
        row (pandas.DataFrame): with 'lt', 'is_ins' labels
                                in 'lt', left-aligned indels are stored
    Returns:
        pos (int): 1-based coordinate
        alt, ref (str): alt or ref allele 
    """
    pos = row["lt"].pos
    if row["is_ins"] == 1:
        ref = "-"
        alt = row["lt"].idl_seq
    else:
        ref = row["lt"].idl_seq
        alt = "-"

    return pos, ref, alt