input: Write a python function to implement the Factory Pattern to create objects based on a specific type of input.
  assert isinstance(create_object('A'), A)
  assert isinstance(create_object('B'), B)
  assert isinstance(create_object('C'), C)
output: class A:
      pass
  
  class B:
      pass
  
  class C:
      pass
  
  def create_object(type):
      if type == 'A':
          return A()
      elif type == 'B':
          return B()
      elif type == 'C':
          return C()
      else:
          raise ValueError("Unknown type")