code: def test_week(self):
      dt = datetime(2017, 5, 19)
      assert self.formatter._format_token(dt, "W") == "2017-W20-5"
  
      # make sure week is zero padded when needed
      dt_early = datetime(2011, 1, 20)
      assert self.formatter._format_token(dt_early, "W") == "2011-W03-4"
  
imports: from datetime import datetime
  import pytest
  import pytz
  from dateutil import tz
  from arrow import FORMAT_ATOM, FORMAT_COOKIE, FORMAT_RFC822, FORMAT_RFC850, FORMAT_RFC1036, FORMAT_RFC1123, FORMAT_RFC2822, FORMAT_RFC3339, FORMAT_RSS, FORMAT_W3C
  from .utils import make_full_tz_list
label_desc: Use image node_id 13 for calling the TestFormatterFormatToken obj's underlying member method code with example usage: obj.test_week() without return types