官方参考文档：https://docs.python.org/3.7/library/_thread.html
_thread库方法
（1） _thread.error
（2）_thread.LockTyoe
（3）_thread.start_new_thread
（4）_thread.interrupt_main
Raise a KeyboardInterrupt exception in the main thread. A subthread can use this function to interrupt the main thread.
（5）_thread.exit
（6）_thread.allocate_lock
import _thread a_lock = _thread.allocate_lock() with a_lock: print("a_lock is locked while this executes")
（7）_thread.get_ident
（8）_thread.stack_size
（9）_thread.TIMEOUT_MAX
（10）lock.acquire(waitflag=1,timeout=-1)
Without any optional argument, this method acquires the lock unconditionally, if necessary waiting until it is released by another thread (only one thread at a time can acquire a lock — that’s their reason for existence).
If the integer waitflag argument is present, the action depends on its value: if it is zero, the lock is only acquired if it can be acquired immediately without waiting, while if it is nonzero, the lock is acquired unconditionally as above.
If the floating-point timeout argument is present and positive, it specifies the maximum wait time in seconds before returning. A negative timeout argument specifies an unbounded wait. You cannot specify a timeout if waitflag is zero.
The return value is True if the lock is acquired successfully, False if not.
（11）lock.release()
（12）lock.locked()