Python set() built-in function
  Python set() built-in function 
   From the Python 3 documentation   Return a new set object, optionally with elements taken from iterable. set is a built-in class. See set and Set Types — set, frozenset for documentation about this class.  
 Examples
 >>> s = set()
>>> s
# set()
>>> type(s)
# <class 'set'>