Plot with "contours" option

Hi @fbeninca

I tried to plot the stereographic map with contours, but it shows error when I use 'contours' option (regardless the projection type.)

# R console

library(reticulate)
plotmap <- import("mapgenerator.plotting.plotmap")
pm <- plotmap$PlotMap()
srcfiles <- '/esarchive/recon/ecmwf/erainterim/monthly_mean/tas_f6h/tas_201804.nc'
srcvars <- 'tas'

pm$plot(srcfiles = srcfiles, srcvars = srcvars, projection = 'NorthPolarStereo', lat = '50-90,10', contours = srcvars, contours_int=20)

Error in py_call_impl(callable, dotsargs, dotskeywords) : ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

Can you help me check where I do wrong? Another question: can contours be another variable from another file?

Many thanks,
An-Chi