Nonetype object has no attribute "output_variables"

[652994331]

please help , I am new to haystack , I met this problem. I am trying to use restapi to use haystack pipeline and add an Prompt Node.
then I got an Nonetype error like below:

it seems this error's because I don't use a prompt template, but I don't know how to define it in my yaml file as I am trying to use a specific prompt like this:

can anyone help me out thank you

[anakin87]

Hello @652994331,
the problem reported by you seems the same of #4924, solved by #4976.
If so, you can install haystack from the main branch.

Let us know if the proposed solution works for you...