Running examples in ‘etl-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: smart_download
> ### Title: Download only those files that don't already exist
> ### Aliases: smart_download
> 
> ### ** Examples
> 
> cars <- etl("mtcars")
No database was specified so I created one for you at:
/home/hornik/tmp/scratch/RtmpPQ6n59/fileca838285432.sqlite3
> urls <- c("https://raw.githubusercontent.com/beanumber/etl/master/etl.Rproj",
+ "https://www.reddit.com/robots.txt")
> smart_download(cars, src = urls)
Downloading 2 new files.  0 untouched.
trying URL 'https://raw.githubusercontent.com/beanumber/etl/master/etl.Rproj'
Content type 'text/plain; charset=utf-8' length 395 bytes
==================================================
downloaded 395 bytes

trying URL 'https://www.reddit.com/robots.txt'
Content type 'text/plain; charset=utf-8' length 786 bytes
==================================================
downloaded 786 bytes

https://raw.githubusercontent.com/beanumber/etl/master/etl.Rproj 
                                                               0 
                               https://www.reddit.com/robots.txt 
                                                               0 
> # won't download again if the files are already there
> smart_download(cars, src = urls)
Downloading 0 new files.  2 untouched.
> # use clobber to overwrite
> smart_download(cars, src = urls, clobber = TRUE)
Downloading 2 new files.  0 untouched.
trying URL 'https://raw.githubusercontent.com/beanumber/etl/master/etl.Rproj'
Content type 'text/plain; charset=utf-8' length 395 bytes
==================================================
downloaded 395 bytes

trying URL 'https://www.reddit.com/robots.txt'
Warning in download.file(url, method = method, ...) :
  cannot open URL 'https://www.reddit.com/robots.txt': HTTP status was '503 Service Unavailable'
Error in download.file(url, method = method, ...) : 
  cannot open URL 'https://www.reddit.com/robots.txt'
Calls: smart_download -> mapply -> <Anonymous> -> download.file
Execution halted