code: def set_address(addr):
      
      # Send DNLOAD with first byte=0x21 and page address
      buf = struct.pack("<BI", 0x21, addr)
      __dev.ctrl_transfer(0x21, __DFU_DNLOAD, 0, __DFU_INTERFACE, buf, __TIMEOUT)
  
      # Execute last command
      if get_status() != __DFU_STATE_DFU_DOWNLOAD_BUSY:
          raise Exception("DFU: set address failed")
  
      # Check command state
      if get_status() != __DFU_STATE_DFU_DOWNLOAD_IDLE:
          raise Exception("DFU: set address failed")
docs: Sets the address for the next operation.