def METHOD_NAME(
    self,
    file_path: StrPath,
    *,
    end_character: str = "\0",
    relative_to: Optional[StrPath] = None,
) -> None:
    """Add file name to the hash. This includes the path.
    Args:
        file_path: Path of the file to add. The full path (or relative) is
            included when adding it to the hash. This is not resolved prior
            to use. It is used as-is unless another argument acts up it.
        end_character: Character that will be added to the end of the file_path.
            This can be an empty string.
        relative_to: Optionally, convert the file_path to path relative to
            this one. It is recommended that both paths be absolute.
    """
    self._hash.update(
        (
            str(
                Path(file_path).relative_to(relative_to)
                if relative_to
                else Path(file_path)
            )
            + end_character
        ).encode()
    )