input: Write a python function to check if a file exists inside a swift container using the given configuration.
  assert check_file_exists({
      "region": "region-a.geo-1",
      "container": "my-container",
      "name": "backups/2023-10-01.zip",
      "token": "example-token",
      "tenantId": "example-tenant-id",
      "identity_url": "http://example.com"
  }) == True
  assert check_file_exists({
      "region": "region-b.geo-2",
      "container": "another-container",
      "name": "backups/2023-09-30.zip",
      "token": "example-token",
      "tenantId": "example-tenant-id",
      "identity_url": "http://example.com"
  }) == False
output: import requests
  
  def check_file_exists(config):
      url = f"{config['identity_url']}/v1/AUTH_{config['tenantId']}/{config['container']}/{config['name']}"
      headers = {
          'X-Auth-Token': config['token']
      }
      
      response = requests.head(url, headers=headers)
      return response.status_code == 200