<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _wait_for_lock(self, lock_file):
 """ Just sleep until the lock_file does not exist or a lock_file-related dynamic recovery flag is spotted :param str lock_file: Lock file to wait upon. """

        sleeptime = .5
        first_message_flag = False
        dot_count = 0
        recover_file = self._recoverfile_from_lockfile(lock_file)
        while os.path.isfile(lock_file):
            if first_message_flag is False:
                self.timestamp("Waiting for file lock: " + lock_file)
                self._set_status_flag(WAIT_FLAG)
                first_message_flag = True
            else:
                sys.stdout.write(".")
                dot_count = dot_count + 1
                if dot_count % 60 == 0:
                    print("")  # linefeed
            # prevents the issue of pypier waiting for the lock file to be gone infinitely
            # in case the recovery flag is sticked by other pipeline when it's interrupted
            if os.path.isfile(recover_file):
                sys.stdout.write(" Dynamic recovery flag found")
                break
            time.sleep(sleeptime)
            sleeptime = min(sleeptime + 2.5, 60)

        if first_message_flag:
            self.timestamp("File unlocked.")
            self._set_status_flag(RUN_FLAG)