<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:

def sdb_get_or_set_hash(uri,
                        opts,
                        length=8,
                        chars='abcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*(-_=+)',
                        utils=None):
    '''
    Check if value exists in sdb.  If it does, return, otherwise generate a
    random string and store it.  This can be used for storing secrets in a
    centralized place.
    '''
    if not isinstance(uri, string_types) or not uri.startswith('sdb://'):
        return False

    if utils is None:
        utils = salt.loader.utils(opts)

    ret = sdb_get(uri, opts, utils=utils)

    if ret is None:
        val = ''.join([random.SystemRandom().choice(chars) for _ in range(length)])
        sdb_set(uri, val, opts, utils)

    return ret or val