code: def test_import_tz_all():
      from dateutil.tz import tzutc
      from dateutil.tz import tzoffset
      from dateutil.tz import tzlocal
      from dateutil.tz import tzfile
      from dateutil.tz import tzrange
      from dateutil.tz import tzstr
      from dateutil.tz import tzical
      from dateutil.tz import gettz
      from dateutil.tz import tzwin
      from dateutil.tz import tzwinlocal
      from dateutil.tz import UTC
      from dateutil.tz import datetime_ambiguous
      from dateutil.tz import datetime_exists
      from dateutil.tz import resolve_imaginary
  
      tz_all = [
          "tzutc",
          "tzoffset",
          "tzlocal",
          "tzfile",
          "tzrange",
          "tzstr",
          "tzical",
          "gettz",
          "datetime_ambiguous",
          "datetime_exists",
          "resolve_imaginary",
          "UTC",
      ]
  
      tz_all += (
          ["tzwin", "tzwinlocal"]
          if sys.platform.startswith("win")
          else []
      )
      lvars = locals()
  
      for var in tz_all:
          assert lvars[var] is not None
  
imports: import sys
  import pytest
label_desc: Use image node_id 17 for calling a global function with example usage: test_import_tz_all() without return types