### How to calculate g-function using pygfunction for GSHP modeling in Energyplus

I try to model ground-source heat pump systems in EnergyPlus.
And I want to use my configuration of borehole, without use value of example files in EnergyPlus.
So, I have to get g-function by using pygfunction to input 'GorundHeatExchanger:ResponseFactors'.
I try to calculate g-function using pygfunction, but I took just graph of g-function, not value of g-function g value, ln(T/Ts) value which is neccesary value to model GSHP system in EnergyPlus.
Please let me know how to get g-function value by using pygfunction.
If you can, I want to get some tips or code for calculation of g-function.
Thanks a lot.