from typing import List
import re


def _remove_lines(txt: str) -> str:
    """
    Remove lines of separating characters long at least 20 characters.
    """
    txt_tmp: List[str] = []
    for line in txt.split("\n"):
        if re.match(r"^\s*[\#\-><=]{20,}\s*$", line):
            continue
        txt_tmp.append(line)
    return "\n".join(txt_tmp)