text: """Constants."""
  from typing import Dict, Iterable, Literal, Union
  
  ONES = frozenset({1, "1", b"1", True})
  ZEROS = frozenset({0, "0", b"0", False})
  PAD = frozenset({"_", " ", ",", "\n", "\r", "\t"})
  ValidBit = Union[bool, Literal[1, 0, "1", "0"]]
  DirtyBits = Union[Iterable, Dict[str, int]]
  