input: Write a python function to compute the Fibonacci sequence up to the nth number.
  assert fibonacci_sequence(0) == [0]
  assert fibonacci_sequence(5) == [0, 1, 1, 2, 3, 5]
  assert fibonacci_sequence(10) == [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55]
output: def fibonacci_sequence(n):
      if n == 0:
          return [0]
      sequence = [0, 1]
      for i in range(2, n+1):
          sequence.append(sequence[-1] + sequence[-2])
      return sequence