<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def acquire(self, *, raise_on_failure=True):
 """Attempt to acquire a slot under this rate limiter. Parameters: raise_on_failure(bool):
 Whether or not failures should raise an exception. If this is false, the context manager will instead return a boolean value representing whether or not the rate limit slot was acquired. Returns: bool: Whether or not the slot could be acquired. """

        acquired = False

        try:
            acquired = self._acquire()
            if raise_on_failure and not acquired:
                raise RateLimitExceeded("rate limit exceeded for key %(key)r" % vars(self))

            yield acquired
        finally:
            if acquired:
                self._release()