DeprecationWarning: the sets module is deprecated from sets import Immut

解决方法：
1) file "__init__", replace:

from sets import ImmutableSet 
class DBAPISet(ImmutableSet): 

with 

class DBAPISet(frozenset)

2) file "converters.py", remove:

from sets import BaseSet, Set

3) file "converters.py", change "Set" by "set" (IMPORTANT: only two places):

line 48或附近: return set([ i for i in s.split(',') if i ])
line 128或附近: set: Set2Str,