code: def p_expr_include_once(p):
      'expr : INCLUDE_ONCE expr'
      p[0] = ast.Include(p[2], True, lineno=p.lineno(1)f p_expr_include_once(p):
      'expr : INCLUDE_ONCE expr'
      p[0] = ast.Include(p[2], True, lineno=p.lineno(1))
docs: expr : INCLUDE_ONCE expr