hi Steven

thanks for check my post

first test have a problem,you didn’t use r+ mode
step is 
1. f.read
2. f.truncate(0)
3. f.write(something)

my test msg tell you

“
tell after delete content 33
content 0 
tell after write 65
“

so you know after truncate f.tell =33
but no content in file
and after you write something into file
msg tell you f.tell =65
but “ {"how_dare_you": "how_dare_you"}” is only 33 length 
so you know must have someing in file

please use editor open the file
you will find it