import re


def install_package_family(pkg):
    """
    :param: pkg ie asr900rsp2-universal.03.13.03.S.154-3.S3-ext.bin
    :return: device_type of the installed image ie asr900
    """
    img_dev = None
    m = re.search(r'(asr\d+)\w*', pkg)
    if m:
        img_dev = m.group(1)

    return img_dev