The ETO.py script will use readily available daily weather data (Temperature max/min, Relative humidity max/min, Solar radiation, Average wind speed), along with latitude and elevation, to calculate Evapotranspiraiton.
It uses the PyETo module to do the heavy lifting. Everything apart from ETO.py and this readme belongs and is credited to PyETo including any licensing.
The script is incomplete, requiring manual entry of data and it just prints out the ETo, but the ETo calculations are all complete.
It has been tested on my local weather data from the Australian Bureau of Meteorology and matches their calculations.