class_docstr: tzinfo class based on win32's timezones available in the registry.
class_docstr_tok: ["tzinfo","class","based","on","win32","'s","timezones","available","in","the","registry","."]
docstr: For a given year, get the DST on and off transition times, expressed
  always on the standard time side. For zones with no transitions, this
  function returns ``None``.
  
  :param year:
      The year whose transitions you would like to query.
  
  :return:
      Returns a :class:`tuple` of :class:`datetime.datetime` objects,
      ``(dston, dstoff)`` for zones with an annual DST transition, or
      ``None`` for fixed offset zones.
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code: def transitions(self, year):
      """
      For a given year, get the DST on and off transition times, expressed
      always on the standard time side. For zones with no transitions, this
      function returns ``None``.
  
      :param year:
          The year whose transitions you would like to query.
  
      :return:
          Returns a :class:`tuple` of :class:`datetime.datetime` objects,
          ``(dston, dstoff)`` for zones with an annual DST transition, or
          ``None`` for fixed offset zones.
      """
  
      if not self.hasdst:
          return None
  
      dston = picknthweekday(
          year,
          self._dstmonth,
          self._dstdayofweek,
          self._dsthour,
          self._dstminute,
          self._dstweeknumber,
      )
  
      dstoff = picknthweekday(
          year,
          self._stdmonth,
          self._stddayofweek,
          self._stdhour,
          self._stdminute,
          self._stdweeknumber,
      )
  
      # Ambiguous dates default to the STD side
      dstoff -= self._dst_base_offset
  
      return dston, dstoff
  
imports: import datetime
  import struct
  from six.moves import winreg
  from six import text_type
  from ._common import tzrangebase
label_desc: Use image node_id 5 for calling the tzwinbase obj's underlying member method code with example usage: obj.transitions(year) and returns: dston,  dstoff, None