input: 
  Write a function to perform vector addition and subtraction for 3-dimensional vectors by defining a python class named Vector. The class should include methods to initialize vectors, print vectors, add two vectors, and subtract two vectors.
  
  class Vector:
      def __init__(self, x, y, z):
          self.x = x
          self.y = y
          self.z = z
          
      def printVec(self):
          print(self.x, self.y, self.z)
          
      def addVec(self, V):
          return Vector(self.x + V.x, self.y + V.y, self.z + V.z)
          
      def subVec(self, V):
          return Vector(self.x - V.x, self.y - V.y, self.z - V.z)
  
  # Test cases
  v1 = Vector(1, 2, 3)
  v2 = Vector(5, 3, 2)
  
  v3 = v1.addVec(v2)
  v4 = v1.subVec(v2)
  
  assert v3.x == 6 and v3.y == 5 and v3.z == 5
  assert v4.x == -4 and v4.y == -1 and v4.z == 1
  
output:     
      def __init__(self, x, y, z):
          self.x = x
          self.y = y
          self.z = z
          
      def printVec(self):
          print(self.x, self.y, self.z)
          
      def addVec(self, V):
          return Vector(self.x + V.x, self.y + V.y, self.z + V.z)
          
      def subVec(self, V):
          return Vector(self.x - V.x, self.y - V.y, self.z - V.z)
  