title: R - Could not find a specific function showing in Source Code of a R package
body: <p>I am studying a R package named "catch", and trying to code that in python. I use "View" function to get the source code from this R package, and find its function "catch" calls another function "tsda". However, I could not find any information about this function "tsda". I tried 
  1. View(tsda)
  2. ?tsda
  3. ??tsda
  4. tsda
  None of them gave me any information. Can anyone tell me how to find this function?</p>