python mcrypt bug when there is a dollar in salt

Question

Look at this:

Python 2.7.6 (default, Oct 26 2016, 20:30:19) 
>>> import crypt
>>> print(crypt.crypt("16409","$1awesome"))
None

if i remove the dollar char:

Python 2.7.6 (default, Oct 26 2016, 20:30:19) 
>>> import crypt
>>> print(crypt.crypt("16409","1awesome"))
1auXW8qPKwars

Do you think this is a bug ?

Thanks