code: def issubset(self, other):
          
          if len(self) > len(other):  # Fast check for obvious cases
              return False
          return all(item in other for item in self)
docs: Report whether another set contains this set.
  
          Example:
              >>> OrderedSet([1, 2, 3]).issubset({1, 2})
              False
              >>> OrderedSet([1, 2, 3]).issubset({1, 2, 3, 4})
              True
              >>> OrderedSet([1, 2, 3]).issubset({1, 4, 3, 5})
              False