A python implementation of Base91 as described on http://base91.sourceforge.net/ , licenced under the New BSD License.
import base91
base91.encode('test') #result: 'fPNKd'
base91.encode(b'\xfe\x03\x00W\xa9\xbc') #result: 'VLv(GdNE'
base91.decode('8D9Kc)=/2$WzeFui#G9Km+<{VT2u9MZil}[A') # result: 'May a moody baby doom a yam?\n'