def decompose_chrstr(peak_str):
    """
    Take peak name as input and return splitted strs.

    Args:
        peak_str (str): peak name.

    Returns:
        tuple: splitted peak name.

    Examples:
       >>> decompose_chrstr("chr1_111111_222222")
       "chr1", "111111", "222222"
    """
    *chr_, start, end = peak_str.split("_")
    chr_ = "_".join(chr_)

    return chr_, start, end