input: 
  class Vector3D:
      """ A Python class representing a 3D Vector with x, y, and z components.
      The class should have a string representation that returns the vector in the 
      format "(x, y, z)".
      Example:
      for Vector3D(1, 2, 3)
      the output should be "(1, 2, 3)"
      """
  
output:     
      def __init__(self, x, y, z):
          self.x = x
          self.y = y
          self.z = z
  
      def __str__(self):
          return f"({self.x}, {self.y}, {self.z})"
  