<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _json_clean(d):
 """Cleans the specified python `dict` by converting any tuple keys to strings so that they can be serialized by JSON. Args: d (dict):
 python dictionary to clean up. Returns: dict: cleaned-up dictionary. """

    result = {}
    compkeys = {}
    for k, v in d.items():
        if not isinstance(k, tuple):
            result[k] = v
        else:
            #v is a list of entries for instance methods/constructors on the
            #UUID of the key. Instead of using the composite tuple keys, we
            #switch them for a string using the 
            key = "c.{}".format(id(k))
            result[key] = v
            compkeys[key] = k

    return (result, compkeys)