Generate clickable map tags if clickable item exists.

        If not exists, this only returns empty string.

def generate_clickable_map(self):
        # type: () -> unicode
        """Generate clickable map tags if clickable item exists.

        If not exists, this only returns empty string.
        """
        if self.clickable:
            return '\n'.join([self.content[0]] + self.clickable + [self.content[-1]])
        else:
            return ''