input: Write a function to generate the nth term of the Fibonacci sequence. If the input is 0, return 0. If the input is 1, return 1. For any other input n, return the sum of the (n-1)th and (n-2)th terms of the Fibonacci sequence.
  assert fibonacci_seq(0)==0
  assert fibonacci_seq(1)==1
  assert fibonacci_seq(5)==5
  assert fibonacci_seq(10)==55
output: def fibonacci_seq(n):
      if n == 0:
          return 0
      elif n == 1:
          return 1
      else:
          a, b = 0, 1
          for _ in range(2, n + 1):
              a, b = b, a + b
          return b