code: def p_annotation_ref(self, p):
          
          if len(p) < 5:
              p[0] = AstAnnotationRef(self.path, p.lineno(1), p.lexpos(1), p[2], None)
          else:
              p[0] = AstAnnotationRef(self.path, p.lineno(1), p.lexpos(1), p[4], p[2])
docs: annotation_ref : AT ID NL
                            | AT ID DOT ID NL