class_docstr: Helper class to allow construction of a list without
  having to reverse it in the end.
code: def build(self):
      return self._head
  
imports: from collections.abc import Sequence, Hashable
  from numbers import Integral
  from functools import reduce
  from typing import Generic, TypeVar
label_desc: Use image node_id 5 for calling the _PListBuilder obj's underlying member method code with example usage: obj.build() and returns: self