input: Write a function to implement a 3-dimensional vector class with methods for vector addition and subtraction. Include methods to print the vector and provide testing code for each method.
  
  def Vector_operations():
      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)
      
      v1 = Vector(1, 2, 3)
      v2 = Vector(5, 3, 2)
      
      assert v1.printVec() == None
      assert v2.printVec() == None
      
      v3 = v1.addVec(v2)
      assert v3.x == 6
      assert v3.y == 5
      assert v3.z == 5
      
      v4 = v1.subVec(v2)
      assert v4.x == -4
      assert v4.y == -1
      assert v4.z == 1
output: 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)