Your code works, you just have to remove the comma at the end of the second line

file_str = f"dbfs:/mnt/dlsi2023/raw/ds_pet_finder_organization{x}.json",

 Should be 

file_str = f"dbfs:/mnt/dlsi2023/raw/ds_pet_finder_organization{x}.json"

 This is what is causing the error.

Also note that