<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_random_hex(length):
 """ Return random hex string of a given length """

    if length <= 0:
        return ''
    return hexify(random.randint(pow(2, length*2), pow(2, length*4)))[0:length]