Clears the paginator to have no pages.

def clear(self):
        """Clears the paginator to have no pages."""
        if self.prefix is not None:
            self._current_page = [self.prefix]
            self._count = len(self.prefix) + 1 # prefix + newline
        else:
            self._current_page = []
            self._count = 0
        self._pages = []