input: def fibonacci(n: int) -> None:
      """Prints Fibonacci series up to a given number n.
      >>> fibonacci(5)
      0 1 1 2 3 
      >>> fibonacci(10)
      0 1 1 2 3 5 8 13 21 34 
      """
      a, b = 0, 1
      if n < 0:
          print("Incorrect input")
      else:
          while a <= n:
              print(a, end=" ")
              a, b = b, a + b
output:     a, b = 0, 1
      if n < 0:
          print("Incorrect input")
      else:
          while a <= n:
              print(a, end=" ")
              a, b = b, a + b