input: Write a python function to compute the nth term of the Fibonacci series.
  assert fibonacci(5) == [0, 1, 1, 2, 3]
  assert fibonacci(10) == [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
  assert fibonacci(1) == [0]
  assert fibonacci(0) == "Please enter a positive integer"
output: def fibonacci(n):
      if n <= 0:
          return "Please enter a positive integer"
      elif n == 1:
          return [0]
      
      fib_series = [0, 1]
      for i in range(2, n):
          fib_series.append(fib_series[i-1] + fib_series[i-2])
      return fib_series