class intSet(object):
	"""An intSet is a set of integers
	The value is represented by a list of ints, self.vals.
	Each int in the set occurs in self.vals exactly once."""

	def __init__(self):
		"""Create an empty set of integers"""
		self.vals = []

	def insert(self, e):
		"""Assumes e is an integer and inserts e into self"""
		if not e in self.vals:
			self.vals.append(e)

	def member(self, e):
		"""Assumes e is an integer
		   Returns True if e is in self, and False otherwise"""
		return e in self.vals

	def remove(self, e):
		"""Assumes e is an integer and removes e from self
		   Raises ValueError if e is not in self"""
		try:
			self.vals.remove(e)
		except:
			raise ValueError(str(e) + ' not found')

	def __str__(self):
		"""Returns a string representation of self"""
		self.vals.sort()
		return '{' + ','.join([str(e) for e in self.vals]) + '}'

	def intersect(self, other):

		return set(self.vals) & set(other.vals)

	def __len__(self):
		#self.vals
		result = []
		for i in set(self.vals):
			i += 1
		return i


set1 = intSet()
set2 = intSet()

for i in range(10,15):
	set1.insert(i)

for i in range(13,18):
	set2.insert(i)


print(set1)
print(set2)
print(set2.intersect(set1))
print(len(set1))