input: Write a python function to return a list of Fibonacci numbers up to a given limit.
  assert fibonacci(10) == [0, 1, 1, 2, 3, 5, 8]
  assert fibonacci(50) == [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
  assert fibonacci(1) == [0, 1]
output: def fibonacci(limit):
      fib_sequence = [0, 1]
      while True:
          next_fib = fib_sequence[-1] + fib_sequence[-2]
          if next_fib > limit:
              break
          fib_sequence.append(next_fib)
      return fib_sequence