code: def exec_stmt(self, exec_loc, body, in_opt):
          
          in_loc, globals, locals = None, None, None
          loc = exec_loc.join(body.loc)
          if in_opt:
              in_loc, globals, locals = in_opt
              if locals:
                  loc = loc.join(locals.loc)
              else:
                  loc = loc.join(globals.loc)
          return ast.Exec(body=body, locals=locals, globals=globals,
                          loc=loc, keyword_loc=exec_loc, in_loc=in_loc)
docs: (2.6, 2.7) exec_stmt: 'exec' expr ['in' test [',' test]]