input: from typing import List
  
  class Vector3D:
      """Represents a 3D vector with components x, y, and z.
      The class should initialize the vector with given x, y, z coordinates
      and provide a string representation of the vector.
  
      >>> vec = Vector3D(1, 2, 3)
      >>> str(vec)
      '(1, 2, 3)'
      >>> vec = Vector3D(0, -1, 0)
      >>> str(vec)
      '(0, -1, 0)'
      """
      def __init__(self, x: float, y: float, z: float):
          self.x = x
          self.y = y
          self.z = z
      
      def __str__(self):
          return "(" + str(self.x) + ", " + str(self.y) + ", " + str(self.z) + ")"
output:     
      def __repr__(self):
          return f"Vector3D({self.x}, {self.y}, {self.z})"
  