code: def p_contents(self, p):
          
          n = len(p)
          if n == 3:
              p[0] = p[1] + [p[2]]
          else:
              p[0] = ['contents', p[1]]
docs: contents : contents statements
                      | contents comment
                      | contents include
                      | contents includeoptional
                      | contents block
                      | statements
                      | comment
                      | include
                      | includeoptional
                      | block