input: Write a python function to generate the first 'n' Fibonacci numbers.
  assert fibonacci(10) == [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
  assert fibonacci(5) == [0, 1, 1, 2, 3]
  assert fibonacci(1) == [0]
output: def fibonacci(n):
      if n == 1:
          return [0]
      fibs = [0, 1]
      while len(fibs) < n:
          fibs.append(fibs[-1] + fibs[-2])
      return fibs