input: Write a function to generate a Python program that displays a Fibonacci sequence of the first n numbers. The function should return the nth Fibonacci number for any positive integer n. If n is 1, return 0, and if n is 2, return 1. For any other n, return the sum of the (n-1)th and (n-2)th Fibonacci numbers.
  
  def fibonacci(n):
      if n == 1:
          return 0
      elif n == 2:
          return 1
      else:
          return fibonacci(n-1) + fibonacci(n-2)
  
  assert fibonacci(1) == 0
  assert fibonacci(2) == 1
  assert fibonacci(3) == 1
  assert fibonacci(4) == 2
  assert fibonacci(5) == 3
  assert fibonacci(6) == 5
  assert fibonacci(7) == 8
output: def fibonacci(n):
      if n == 1:
          return 0
      elif n == 2:
          return 1
      else:
          return fibonacci(n-1) + fibonacci(n-2)