class_docstr: Indicator for padded values.
  
  >>> from gluonts.zebras import time_series
  >>> ts = time_series([1, 2, 3]).pad(0, left=2, right=2)
  >>> assert len(ts == 7)
  >>> assert list(ts) == [0, 0, 1, 2, 3, 0, 0]
  >>> assert ts._pad.left == 2
  >>> assert ts._pad.right == 2
class_docstr_tok: ["Indicator","for","padded","values",".",">",">",">","from","gluonts.zebras","import","time_series",">",">",">","ts","=","time_series","(","[","1",",","2",",","3","]",")",".pad","(","0",",","left=2",",","right=2",")",">",">",">","assert","len","(","ts","==","7",")",">",">",">","assert","list","(","ts",")","==","[","0",",","0",",","1",",","2",",","3",",","0",",","0","]",">",">",">","assert","ts._pad.left","==","2",">",">",">","assert","ts._pad.right","==","2"]
code: def extend(self, left, right):
      return Pad(
          left=max(0, self.left + left),
          right=max(0, self.right + right),
      )
  
imports: from __future__ import annotations
  import dataclasses
  from typing import Any, Optional, NamedTuple, Union
  from typing_extensions import Literal
  from gluonts import maybe
  from ._period import Periods, Period
  from ._util import _replace
label_desc: Use image node_id 1 for calling the Pad obj's underlying member method code with example usage: obj.extend(left, right) and returns: Pad