input: Write a function to print the Fibonacci series up to a given number.
  Next, provide a specific example:
  def fibonacci(n): 
      a, b = 0, 1
      if n < 0: 
          print("Incorrect input") 
      else: 
          while a <= n:
              print(a, end=" ")
              a, b = b, a + b 
  
  assert fibonacci(10) == None
  assert fibonacci(20) == None
  assert fibonacci(0) == None
  assert fibonacci(1) == None
  assert fibonacci(-1) == None
output: def fibonacci(n): 
      a, b = 0, 1
      if n < 0: 
          print("Incorrect input") 
      else: 
          while a <= n:
              print(a, end=" ")
              a, b = b, a + b