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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 _is_alphanum(cls, c):
 """ Returns True if c is an uppercase letter, a lowercase letter, a digit or an underscore, otherwise False. :param string c: Character to check :returns: True if char is alphanumeric or an underscore, False otherwise :rtype: boolean TEST: a wrong character False """


        alphanum_rxc = re.compile(CPEComponentSimple._ALPHANUM_PATTERN)
        return (alphanum_rxc.match(c) is not None)