for sub_tree in parse.subtrees(): AttributeError: 'str' object has no attribute 'subtrees'

这个错误通常出现在尝试对字符串类型进行树形解析的时候。可能是在调用`subtrees()`方法之前，没有将字符串正确地转换为树形结构。

你可以检查一下代码中是否有将字符串传递给了树形解析器，而没有将其正确地转换为树形结构。如果是这样，你可以使用树形解析器提供的方法（如`fromstring()`或`fromtext()`）将字符串转换为树形结构。然后再调用`subtrees()`方法进行解析。

相关问题

AttributeError: 'Namespace' object has no attribute 'save_dir'

This error means that you are trying to access an attribute called `save_dir` from an object of the class `Namespace`, but this attribute does not exist in that object.

To fix this error, make sure that you have defined the `save_dir` attribute in your object before trying to access it. You can do this by either setting the attribute directly or by passing it as a command line argument when running your program.

For example, if you are using the argparse module to parse command line arguments, you can define the `save_dir` attribute like this:

import argparse

parser = argparse.ArgumentParser()
parser.add_argument('--save_dir', type=str, default='.')
args = parser.parse_args()

# Now you can access the save_dir attribute like this:
print(args.save_dir)

If you are not using argparse, make sure you define the `save_dir` attribute in your object before trying to access it.