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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_crash_signature(error_line):
 """Try to get a crash signature from the given error_line string."""

    search_term = None
    match = CRASH_RE.match(error_line)
    if match and is_helpful_search_term(match.group(1)):
        search_term = match.group(1)
    return search_term