Using types-lxml types in external code

[roblframpton]

This library does a great job of typing the results from lxml functions. I can see, for example, that the XML parse method returns a type _ElementTree[_Element]. However, I cannot see a way to use these types in my own code. For example, I'd like to write a method which takes an ElementTree as an argument:

def my_func(element: _ElementTree[_Element]):
  pass

but I can't work out how to import these types. I tried:

from types_lxml import _ElementTree, _Element

but this didn't work. So:

1. Is there a way to import these types to use in our own code?
2. Could this be documented somewhere in the readme?

Thanks!

[abelcheung]

Is there a way to import these types to use in our own code?

First things first, actually it is expected to only import classes from source, not from external stubs directly.

And there are a few ways to migitate the problem:

1. Quote the type with double quotes so python interpreter would treat annotation as strings

   from lxml.etree import _ElementTree, _Element
   def my_func(element: "_ElementTree[_Element]"):
     pass

2. Use __future__:

   from __future__ import annotations
   from lxml.etree import _ElementTree, _Element
   def my_func(element: _ElementTree[_Element]):
     pass

(2) automatically helps achieving (1) for you without your intervention, but you would need to remember adding __future__ to the very top of every file where it is used.

Could this be documented somewhere in the readme?

Yes, the documentation absolutely needs some love. I think I can get something done after clearing my current tasks at hand. I'll leave the report open for now as reminder.

[roblframpton]

Thanks a lot for your response, that has solved things for me.

[abelcheung]

Doc now available on wiki.