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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 exclude_chars(text, exclusion=None):
 """ Clean text string of simbols in exclusion list. """

    exclusion = [] if exclusion is None else exclusion
    regexp = r"|".join([select_regexp_char(x) for x in exclusion]) or r''
    return re.sub(regexp, '', text)