import re


def remove_strike(string):
    """replace strike tags and leading and tailing whitespace"""
    if not string:
        return ""
    for match in re.finditer(r"\s*<strike>.*?</strike>\s*", string):
        # replace with blank string unless flanked by spaces replace with a space char
        replace_char = ""
        if match.group(0).startswith(" ") and match.group(0).endswith(" "):
            replace_char = " "
        string = string.replace(match.group(0), replace_char)
    return string