<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def set_value(self, k, v):
 """Set a value on the proxy, parsing it to a useful datatype if possible"""

        from ast import literal_eval
        if self.engine is None or self.proxy is None:
            self._trigger_set_value(k, v)
            return
        if v is None:
            del self.proxy[k]
        else:
            try:
                vv = literal_eval(v)
            except (TypeError, ValueError):
                vv = v
            self.proxy[k] = vv