input: Write a python function to generate Fibonacci sequence of a given length.
  assert getFibonacciSequence(5) == [0, 1, 1, 2, 3]
  assert getFibonacciSequence(8) == [0, 1, 1, 2, 3, 5, 8, 13]
  assert getFibonacciSequence(1) == [0, 1]
output: def getFibonacciSequence(n):
      if n <= 0:
          return []
      elif n == 1:
          return [0, 1]
      fib_seq = [0, 1]
      for _ in range(2, n):
          fib_seq.append(fib_seq[-1] + fib_seq[-2])
      return fib_seq