Error while compilation Esp32 and UART Openmv RPC

I tried compiling the hardware serial openmv Arduino RPC library for esp32 board in Arduino idea but it keeps running into error during compilation. I’ve tried the hardware serial for esp32 with serial, serial1, serial2, serial3 the class doesn’t still name a type…
Error is always:
“openmv::rpc_hardware_serial_uart_master doesn’t name a type”

…pls could someone suggest a solution