input: Write a python function to fetch and print user names from a given URL using the requests library.
  assert fetch_user_names('https://jsonplaceholder.typicode.com/users') is None
  assert fetch_user_names('https://mockapi.io/users') is None
output: def fetch_user_names(url):
      import requests
  
      response = requests.get(url)
      if response.status_code == 200:
          users = response.json()
          for user in users:
              print(user['name'])