code: def import_from_string(path, slient=True):
      
      names = path.split(".")
      for i in range(len(names), 0, -1):
          p1 = ".".join(names[0:i])
          module = import_module(p1)
          if module:
              p2 = ".".join(names[i:])
              if p2:
                  return select(module, p2, slient=slient)
              else:
                  return module
      name = names[0]
      names = names[1:]
      module = get_caller_locals().get(name)
      if module and names:
          return select(module, ".".join(names), slient=slient)
      if module:
          return module
      module = get_caller_globals().get(name)
      if module and names:
          return select(module, ".".join(names), slient=slient)
      if module:
          return module
      if slient:
          return None
      else:
          raise ImportError("Import {path} failed.".format(path=path))
docs: 根据给定的对象路径，动态加载对象。