def get_specific_str(big_str, prefix, suffix):
    """
    Extract a specific length out of a string

    :param big_str: string to reduce
    :param prefix: prefix to remove
    :param suffix: suffix to remove
    :return: string reduced, return empty string if prefix/suffix not present
    """
    specific_str = big_str
    if prefix and len(specific_str.split(prefix)) > 1:
        specific_str = specific_str.split(prefix)[1]
    if suffix and len(specific_str.split(suffix)) > 1:
        specific_str = specific_str.split(suffix)[0]
    if specific_str != big_str:
        return specific_str
    else:
        return ''