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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 unlinkUser(self, delete=False):
 """Unlink the user to the Contact :returns: True if OK, False if no User was unlinked :rtype: bool """

        userid = self.getUsername()
        user = self.getUser()
        if user:
            logger.debug("Unlinking User '{}' from Contact '{}'".format(
                userid, self.Title()))

            # Unlink the User
            if not self._unlinkUser():
                return False

            # Also remove the Plone User (caution)
            if delete:
                logger.debug("Removing Plone User '{}'".format(userid))
                api.user.delete(username=userid)

            return True
        return False