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