from typing import List
import re


def alphawords(text: str, underscore: bool = False) -> List[str]:
    """Returns all alpha character sequences from the `text`.

    If `underscore` is True, the '_' is also treated as an alpha character.
    """
    if underscore:
        return re.findall(r"[^\W\d]+", text)
    else:
        return re.findall(r"[^\W\d_]+", text)