gh-104050: Argument Clinic: Annotate the BufferSeries class

Tools/clinic/clinic.py

@@ -1965,12 +1965,12 @@ class BufferSeries:
  e.g. o[-1] is an element immediately preceding o[0].
  """
 
- def __init__(self):
+ def __init__(self) -> None:
  self._start = 0
- self._array = []
+ self._array: list[_TextAccumulator] = []
  self._constructor = _text_accumulator
 
- def __getitem__(self, i):
+ def __getitem__(self, i: int) -> _TextAccumulator:
  i -= self._start
  if i < 0:
  self._start += i
@@ -1981,11 +1981,11 @@ def __getitem__(self, i):
  self._array.append(self._constructor())
  return self._array[i]
 
- def clear(self):
+ def clear(self) -> None:
  for ta in self._array:
  ta.text.clear()
 
- def dump(self):
+ def dump(self) -> str:
  texts = [ta.output() for ta in self._array]
  return "".join(texts)