UndefVarError when using GeoRDD in julia

i am using julia1.8.5 version. when i run “Pkg.precompile()” in julia, there is a error “Failed to precompile GeoRDD”, specificly “LoadError: UndefVarError: xcoord not defined”. Then I run"]add GitHub - maximerischard/GeoRDD.jl: Geographical Regression Discontinuity Designs using Gaussian Process Regression’’ in julia, there is no error prompt.But when i run"using GeoRDD" ,there is again a error of “UndefVarError: xcoord not defined”. what should i do to deal with it. can anyone help?