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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 set_ctype(self, ctype, orig_ctype=None):
 """ Set the selected content type. Will not override the value of the content type if that has already been determined. :param ctype: The content type string to set. :param orig_ctype: The original content type, as found in the configuration. """


        if self.ctype is None:
            self.ctype = ctype
            self.orig_ctype = orig_ctype