input: 
  def create_3D_Vector_class() -> str:
      """ Create the definition of a Python class which represents a 3D Vector.
      The class should have an initializer (__init__) that takes three parameters: x, y, and z.
      It should also have a __str__ method that returns a string representation of the vector in the format "(x, y, z)".
      Return the class definition as a string.
      Example:
      for create_3D_Vector_class() == "class Vector3D:\n    def __init__(self, x, y, z):\n        self.x = x\n        self.y = y\n        self.z = z\n    \n    def __str__(self):\n        return '(' + str(self.x) + ', ' + str(self.y) + ', ' + str(self.z) + ')'"
      """
  
output:     
  class Vector3D:
      def __init__(self, x, y, z):
          self.x = x
          self.y = y
          self.z = z
      
      def __str__(self):
          return '(' + str(self.x) + ', ' + str(self.y) + ', ' + str(self.z) + ')'
  