Where is wt() function in R

Question

I cannot seem to find the wt() function in R used on this page: Combine base and ggplot graphics in R figure window

wt.t1=wt(t1)

I could not find it in ??wt and on searching on google. It must be in some package. There is no library statement on the above page. Thanks for your help.

Answer 1

wt() is just a plotting function used in that example. Above it is the line

require(biwavelet) 

and looking at the biwavelet package they have a wt() function defined. That function is certainly not required for combing plots; it was only part of the reproducible example.