fix block size

[antazoey]

Environment information

Block size is not being calculated correctly.

What went wrong?

Please include information like:

• what command you ran
• the code that caused the failure (see this link for help with formatting code)
• full output of the error you received

How can it be fixed?

Fill this in if you have ideas on how the bug could be fixed.

[antazoey]

I don't think this possible in Starknet yet, so we are waiting