Problem in gst mad in Ubuntu 16.04

Traceback (most recent call last):
File "", line 1, in
File "/usr/lib/python2.7/site-packages/dbr/dbr.py", line 22, in
main()
File "/usr/lib/python2.7/site-packages/dbr/dbr.py", line 13, in main
r = reproductor.Reproductor()
File "/usr/lib/python2.7/site-packages/dbr/reproductor.py", line 27, in __init__
decoder = gst.element_factory_make("mad", "mp3-decoder")
gst.ElementNotFoundError: mad