class frozenset(object)|  frozenset() -> empty frozenset object|  frozenset(iterable) -> frozenset object|  |  Build an immutable unordered collection of unique elements.    # 创建一个不可变得，无序的，元素唯一的集合|  |  Methods defined here:|  |  __and__(self, value, /)|      Return self&value.|  |  __contains__(...)|      x.__contains__(y) <==> y in x.|  |  __eq__(self, value, /)|      Return self==value.|  |  __ge__(self, value, /)|      Return self>=value.|  |  __getattribute__(self, name, /)|      Return getattr(self, name).|  |  __gt__(self, value, /)|      Return self>value.|  |  __hash__(self, /)|      Return hash(self).|  |  __iter__(self, /)|      Implement iter(self).|  |  __le__(self, value, /)|      Return self<=value.|  |  __len__(self, /)|      Return len(self).|  |  __lt__(self, value, /)|      Return self<value.|  |  __ne__(self, value, /)|      Return self!=value.|  |  __new__(*args, **kwargs) from builtins.type|      Create and return a new object.  See help(type) for accurate signature.|  |  __or__(self, value, /)|      Return self|value.|  |  __rand__(self, value, /)|      Return value&self.|  |  __reduce__(...)|      Return state information for pickling.|  |  __repr__(self, /)|      Return repr(self).|  |  __ror__(self, value, /)|      Return value|self.|  |  __rsub__(self, value, /)|      Return value-self.|  |  __rxor__(self, value, /)|      Return value^self.|  |  __sizeof__(...)|      S.__sizeof__() -> size of S in memory, in bytes|  |  __sub__(self, value, /)|      Return self-value.|  |  __xor__(self, value, /)|      Return self^value.|  |  copy(...)|      Return a shallow copy of a set.|  |  difference(...)|      Return the difference of two or more sets as a new set.|      |      (i.e. all elements that are in this set but not the others.)|  |  intersection(...)|      Return the intersection of two sets as a new set.|      |      (i.e. all elements that are in both sets.)|  |  isdisjoint(...)|      Return True if two sets have a null intersection.|  |  issubset(...)|      Report whether another set contains this set.|  |  issuperset(...)|      Report whether this set contains another set.|  |  symmetric_difference(...)|      Return the symmetric difference of two sets as a new set.|      |      (i.e. all elements that are in exactly one of the sets.)|  |  union(...)|      Return the union of sets as a new set.|      |      (i.e. all elements that are in either set.)