Your version is : v0.5.4-64
I just installed the latest version : v0.5.4-66
You can see the commit in the mraa repo : api/spi: Add Spi_Modes to CPP headers. · 62c3264 · intel-iot-devkit/mraa · GitHub
if you do a dir(mraa) you will find this :
'SPI_MODE0', 'SPI_MODE1', 'SPI_MODE2', 'SPI_MODE3'
then you should be able to do
spi.mode(mraa.SPI_MODE2)
Enjoy!
ps:
thanks to Thomas Ingleby