input: Write a function to print the Fibonacci series up to a given number.
  assert fibonacci(5)==[0, 1, 1, 2, 3]
  assert fibonacci(10)==[0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
  assert fibonacci(0)==[]
  assert fibonacci(1)==[0]
  assert fibonacci(-1)==[]
output: def fibonacci(n):
      if n < 0:
          return []
      if n == 0:
          return []
      if n == 1:
          return [0]
      fib_series = [0, 1]
      while len(fib_series) < n:
          fib_series.append(fib_series[-1] + fib_series[-2])
      return fib_series[:n]