input: Write a function to calculate the Fibonacci number at a given position. Implement a recursive approach to solve this problem. Return the Fibonacci number corresponding to the given position.
  
  def fibonacci(n):
      if n == 0:
          return 0
      elif n == 1:
          return 1
      else:
          return fibonacci(n-1) + fibonacci(n-2)
  
  assert fibonacci(0) == 0
  assert fibonacci(1) == 1
  assert fibonacci(5) == 5
  assert fibonacci(10) == 55
output: def fibonacci(n):
      if n == 0:
          return 0
      elif n == 1:
          return 1
      else:
          return fibonacci(n-1) + fibonacci(n-2)