input: Write a python function to generate the first n Fibonacci numbers.
  assert fibonacci(5) == [1, 2, 3, 5, 8]
  assert fibonacci(8) == [1, 2, 3, 5, 8, 13, 21, 34]
  assert fibonacci(0) == [1]
output: def fibonacci(n):
      if n == 0:
          return [1]
      fib = [1, 2]
      while len(fib) < n:
          fib.append(fib[-1] + fib[-2])
      return fib[:n]