code: def p_annotation(self, p):
          '''annotation : IDENTIFIER '=' LITERAL
                        | IDENTIFIER'''
  
          if len(p) == 4:
              p[0] = ast.Annotation(p[1], p[3], lineno=p.lineno(1))
          else:
              p[0] = ast.Annotation(p[1], True, lineno=p.lineno(1)f p_annotation(self, p):
          '''annotation : IDENTIFIER '=' LITERAL
                        | IDENTIFIER'''
  
          if len(p) == 4:
              p[0] = ast.Annotation(p[1], p[3], lineno=p.lineno(1))
          else:
              p[0] = ast.Annotation(p[1], True, lineno=p.lineno(1))
docs: annotation : IDENTIFIER '=' LITERAL
                        | IDENTIFIER