code: def tzparse(tz):
      # If no object has been provided by the user and a timezone can be
      # found via contractdtails, then try to get it from pytz, which may or
      # may not be available.
      tzstr = isinstance(tz, string_types)
      if tz is None or not tzstr:
          return Localizer(tz)
  
      try:
          import pytz  # keep the import very local
      except ImportError:
          return Localizer(tz)  # nothing can be done
  
      tzs = tz
      if tzs == "CST":  # usual alias
          tzs = "CST6CDT"
  
      try:
          tz = pytz.timezone(tzs)
      except pytz.UnknownTimeZoneError:
          return Localizer(tz)  # nothing can be done
  
      return tz
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  import datetime
  import math
  import time
  from .py3 import string_types
label_desc: Use image node_id 1 for calling a global function with example usage: tzparse(tz) and returns: tz, Localizer, Localizer, Localizer