How to specify paris fork using custom spec?

[Deniallugo]

In chain spec this param is skipped.

reth/crates/primitives/src/chain/spec.rs

Line 477 in 024bb26

pub paris_block_and_final_difficulty: Option<(u64, U256)>,

And it's not set by itself if you use a custom JSON chain.spec, as a result, the fork is not activated for the chain with custom spec

[Deniallugo]

#7111
Solved here