How to add new field / manipulate geo data for object created in geotables in Julia

Question

I'm new to Julia - I'm planning to run some simulations that take ages to run in R.

So, I want to add a field to an object I imported with GeoTables. I'm having a lot of trouble finding any information on how to do this.

My original approach was:

# Read shapefile
htDHS_t1_shp = GeoTables.load(htDHS_t1_path) |> GeoData

#%% Displace Coordinates
# Generate a random angle for each feature by generating an angle between 0 and 360, and converting from degrees to radians.

# empty field in dataset_shp
dataset_shp.angle_rand .= []
# calculate new random value for each feature
dataset_shp.angle_rad .= (rand() * 360) * (pi / 180)

I'm not sure if any of this is at all close to being correct. In R, with the sf package, it would just be a simple:

dataset_shp$angle_rad <- (runif(1)*360) * (pi / 180)

But can't seem to figure out how to match this functionality with GeoTables in Julia.

Thanks in advance for any attention!