optimize sleep func fix error in thread

maix/__init__.py

@@ -4,8 +4,11 @@
 from ._maix.peripheral.key import add_default_listener
 from .__signal_handle__ import register_signal_handle
 from ._maix.util import register_atexit
+from . import __maix_time__
 from . import _maix
 
+del __maix_time__ # update time module then delete
+
 register_signal_handle()
 del register_signal_handle
 

maix/__maix_time__.py

@@ -0,0 +1,12 @@
+from . import _maix
+import time
+
+def sleep_ms(ms : int):
+    time.sleep(ms * 0.001)
+
+def sleep_us(us: int):
+    time.sleep(us * 0.000001)
+
+_maix.time.sleep = time.sleep
+_maix.time.sleep_ms = sleep_ms
+_maix.time.sleep_us = sleep_us