Bug with ST32F411CEU6 V3.1 in arduino programming, Platformio and STM32LowPower lib (STM32duino Low Power)

[sfekilou]

With Black Pill ST32F411CEU6, arduino coding, platformio

If the code is:
``
void setup() {
pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
digitalWrite(LED_BUILTIN, HIGH);
delay(1000);
digitalWrite(LED_BUILTIN, LOW);
delay(1000);
}
``

The LED is blinking.

But if the code is:
`
#include <STM32LowPower.h> //Last STM32duino Low Power lib
void setup() {
pinMode(LED_BUILTIN, OUTPUT);
LowPower.begin();
}

void loop() {
digitalWrite(LED_BUILTIN, HIGH);
LowPower.deepSleep(2000);
digitalWrite(LED_BUILTIN, LOW);
LowPower.deepSleep(2000);
}
`
The LED does not blinking
What is the problem ?
Do you know a method to perform a deepsleep ?