class_docstr: Determines the timezone of a datetime.
  
  Description:
      Given a list of datetimes, extract the timezone from each
      one. Looks for the `tzinfo` attribute on `datetime.datetime`
      objects. If the datetime has no timezone or the date is
      missing, return `NaN`.
  
  Examples:
      >>> from datetime import datetime
      >>> from pytz import timezone
      >>> date_to_time_zone = DateToTimeZone()
      >>> dates = [datetime(2010, 1, 1, tzinfo=timezone("America/Los_Angeles")),
      ...          datetime(2010, 1, 1, tzinfo=timezone("America/New_York")),
      ...          datetime(2010, 1, 1, tzinfo=timezone("America/Chicago")),
      ...          datetime(2010, 1, 1)]
      >>> date_to_time_zone(dates).tolist()
      ['America/Los_Angeles', 'America/New_York', 'America/Chicago', nan]
code: def get_function(self):
      def date_to_time_zone(x):
          return x.apply(
              lambda x: x.tzinfo.zone if x.tzinfo else np.nan
          )
  
      return date_to_time_zone
  
imports: import numpy
  from woodwork.column_schema import ColumnSchema
  from woodwork.logical_types import Categorical, Datetime
  from featuretools.primitives.base import TransformPrimitive
label_desc: Use image node_id 1 for calling the DateToTimeZone obj's underlying member method code with example usage: obj.get_function() and returns: date_to_time_zone, x