code: def __init__(
      self,
      std_abbr,
      std_offset,
      dst_abbr,
      dst_offset,
      start=None,
      end=None,
  ):
      self.dst_diff = dst_offset - std_offset
      std_offset = _load_timedelta(std_offset)
      self.std = _ttinfo(
          utcoff=std_offset, dstoff=_load_timedelta(0), tzname=std_abbr
      )
  
      self.start = start
      self.end = end
  
      dst_offset = _load_timedelta(dst_offset)
      delta = _load_timedelta(self.dst_diff)
      self.dst = _ttinfo(
          utcoff=dst_offset, dstoff=delta, tzname=dst_abbr
      )
  
      # These are assertions because the constructor should only be called
      # by functions that would fail before passing start or end
      assert start is not None, "No transition start specified"
      assert end is not None, "No transition end specified"
  
      self.get_trans_info = self._get_trans_info
      self.get_trans_info_fromutc = self._get_trans_info_fromutc
  
imports: import bisect
  import calendar
  import collections
  import functools
  import re
  import weakref
  from datetime import datetime, timedelta, tzinfo
  from .None import _common, _tzpath
label_desc: Use image node_id 1 to create a new _TZStr object  with example: obj = _TZStr(std_abbr, std_offset, dst_abbr, dst_offset, start, end)