<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(self, name, value, autodeclare=False):
 """Set the value of a key. This method will cause anyone waiting on a key (and any future waiters) to unblock and be returned the value you pass here. If the key has not been declared previously, a KeyError() is raised unless you pass ``autodeclare=True`` which will cause the key to be declared. Normally you don't want to autodeclare. This method is not a coroutine and does not block. Args: name (str):
 The key to set value (object):
 The value to set autodeclare (bool):
 Whether to automatically declare the key if is has not already been declared. Defaults to False. """


        if not autodeclare and name not in self._data:
            raise KeyError("Key {} has not been declared and autodeclare=False".format(name))

        self._ensure_declared(name)
        self._data[name].set_result(value)