input: Write a function to print the Fibonacci series up to n numbers where n is a user input.
  
  assert fibonacci_series(10)=="Fibonacci Series: 0 1 1 2 3 4 5 6 7 8"
  assert fibonacci_series(5)=="Fibonacci Series: 0 1 1 2 3"
  assert fibonacci_series(0)=="Fibonacci Series:"
  assert fibonacci_series(1)=="Fibonacci Series: 0"
  assert fibonacci_series(2)=="Fibonacci Series: 0 1"
output: def fibonacci_series(n):
      if n == 0:
          return "Fibonacci Series:"
      elif n == 1:
          return "Fibonacci Series: 0"
      elif n == 2:
          return "Fibonacci Series: 0 1"
      
      fib_series = [0, 1]
      for i in range(2, n):
          fib_series.append(fib_series[-1] + fib_series[-2])
      
      return "Fibonacci Series: " + " ".join(map(str, fib_series))