boxr has a few very simple S3 classes for the data returned by the API.
  While httr returns objects in it's own system of classes,
  generally boxr extracts information, and converts the JSON response to an R
  list with httr::content (perhaps with some information judged
  to be extraneous removed). If you'd rather get to the list itself, you can
  do this with  unclass(x).
  
  The following classes are used:
  
  
box_ul, and similar functions (e.g. 
      box_save). A description of a file remotely hosted on 
      box.com. Available methods: print.
    
print
    
box_search, and related functions. A list,
      with each entry being a reference to a file or folder hosted on box.com
      . Available methods: print, for a summary of the first few
      results, and as.data.frame, to coerce some of the API response's
      information to a data.frame.
    
box_dir_diff. Available
      methods: print, summary.
    
box_fetch and box_push.
      Available methods: print, summary