input: Write a function to generate and print the Fibonacci series up to n numbers where n is provided by the user. The function should prompt the user for the value of n, then print the Fibonacci series accordingly. If the user inputs 0, the function should print nothing.
  assert fibonacci_series(5) == "0 1 1 2 3"
  assert fibonacci_series(0) == ""
  assert fibonacci_series(1) == "0"
  assert fibonacci_series(2) == "0 1"
  assert fibonacci_series(10) == "0 1 1 2 3 5 8 13 21 34"
output: def fibonacci_series(n):
      if n == 0:
          return ""
      if n == 1:
          return "0"
      fib_series = [0, 1]
      for i in range(2, n):
          fib_series.append(fib_series[-1] + fib_series[-2])
      return " ".join(map(str, fib_series))