<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _try_lookup(table, value, default = ""):
 """ try to get a string from the lookup table, return "" instead of key error """

    try:
        string = table[ value ]
    except KeyError:
        string = default
    return string