output problem in embedded python block

[JORGE GONZALEZ ORELLANA]

Hi all, I have been writing a python block that takes the content from a file and append a vector of 0s, so the output of the block is the file content plus a certain amount of 0s (the amount of 0s it a parameter) but I can't get an output from the block, in the workflow I connect the python block to a file sink block.

¿Does anyone know why I can't get any output?

I attach a screenshot of the entire code

Screenshot from 2023-05-11 14-20-43.png
Description: PNG image