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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 detect(self, fstring, fname=None):
 """Have a stab at most files."""

        if fname is not None and '.' in fname:
            extension = fname.rsplit('.', 1)[1]
            if extension in {'pdf', 'html', 'xml'}:
                return False
        return True