I wrote the code to make sure that 0.1 plus 10 times doesn't get 1, but it doesn't work.

a=0
for i in range(10):
a+=0.1
a

I wrote the code to make sure that 0.1 is added 10 times but it doesn't work.
What's wrong?

Edit
I'm sorry I didn't know the function of editing.
I don't know what to write even if it's called a running environment, but I use Jupiter Notebook from anaconda software.
When I deleted the previous one and started over from the beginning, it was displayed as follows.
Is there something wrong with a?

File "C:\Users\user\AppData\Local\Temp\ipykernel_13580\1575381174.py", line 3
a+=0.1
^
IndentationError: expected an indented block