错误没有适用于“ ggplot_build”的适用于“网格”类对象的方法

我想在使用randomForest，partial和plotPartial之后为3个（多）部分依赖图创建一个通用图例。每当我尝试任何建议的解决方案时，它都会带来：

Error in UseMethod("ggplot_build") : 
  no applicable method for 'ggplot_build' applied to an object of class "trellis"

这是我的代码的示例：

data(boston, package = "pdp") # load the (corrected) Boston housing data

library(pdp)
library(randomForest) # for randomForest, partialPlot, and varImpPlot functions
set.seed(101) # for reproducibility
boston.rf <- randomForest(cmedv ~ ., data = boston, importance = TRUE)
varImpPlot(boston.rf)


# Compute partial dependence data for lstat and rm
pd <- partial(boston.rf, pred.var = c("lstat", "rm"))
# Default PDP
a <- plotPartial(pd)

# Compute partial dependence data for lstat and dis
pd2 <- partial(boston.rf, pred.var = c("lstat", "dis"))
# Default PDP
b <- plotPartial(pd2)

# Compute partial dependence data for rm and dis
pd3 <- partial(boston.rf, pred.var = c("rm", "dis"))
# Default PDP
c <- plotPartial(pd3)

grid_arrange_shared_legend(a,b,c, ncol = 3, nrow = 1)