code: def p_alias(self, p):
          
          if p[1] == 'alias':
              has_annotations = len(p) > 6 and p[7] is not None
              doc = p[8] if len(p) > 6 else None
              p[0] = AstAlias(
                  self.path, p.lineno(1), p.lexpos(1), p[2], p[4], doc)
              if has_annotations:
                  p[0].set_annotations(p[7])
          else:
              raise ValueError('Expected alias keyword')
docs: alias : KEYWORD ID EQ type_ref NL
                   | KEYWORD ID EQ type_ref NL INDENT annotation_ref_list docsection DEDENT