a model created from the LDA(), JST() or rJST() function and
estimated with fit()
nWords
the number of words per topic/sentiment to display in the outer
layer of the plot
layers
specifies the number of layers for the sunburst chart. This
will restrict the output to the layers uppermost levels of the chart. For
example, setting layers = 1 will only display the top level of the
hierarchy (topics for an LDA model).
sort
if TRUE, sorts the plotted topics in a decreasing frequency.