[Scripting Question] National Dex requires that mon to evolve like in FRLG inspiration

[theRiolvile]

So I had a script for my fangame which I never released on my Gen 1 game with the script or Switch which prevent certain species from evolving if not having the Nationaldex ,you know the Crobat and Blissey dilema now I was looking around in my old backup of my project to update it to V20.1 but that .rb file I cant find where it could be I have check if it is in PokemonUtilites
But I am very very sure its one of the switches since I havent worked on my project in a longtime the script may be lost since moving all of it to the new version or beter I would appriate it.
.

Spoiler:

def check_evolution_internal
return nil if egg? || shadowPokemon?
return nil if hasItem?(:EVERSTONE)
return nil if hasAbility?(:BATTLEBOND)
species_data.get_evolutions(true).each do |evo| # [new_species, method, parameter, boolean]
next if evo[3] # Prevolution
if !$player.pokedex.unlocked?(-1)
if Settings::USE_CURRENT_REGION_DEX
region = pbGetCurrentRegion
region = -1 if region >= dexes_count - 1
next if !pbAllRegionalSpecies(region).include?(evo[0])
else
has_dex=false
$player.pokedex.dexes_count.times do |i|
dex_list_to_check = (i == $player.pokedex.dexes_count - 1) ? -1 : i
next if dex_list_to_check == -1
next if !$player.pokedex.unlocked?(i)
if pbAllRegionalSpecies(i).include?(evo[0])
has_dex=true
break
end
end
next unless has_dex
end
end
ret = yield self, evo[0], evo[1], evo[2] # pkmn, new_species, method, parameter
return ret if ret
end
return nil
end

Edit:I have found it but the thing is will it be easier to bind it to a switch for an option for the player to pick if they want the old experience something like that.

 

[Swdfm]

DONT_CARE_ABOUT_DEXES = 69

def check_evolution_internal
  return nil if egg? || shadowPokemon?
  return nil if hasItem?(:EVERSTONE)
  return nil if hasAbility?(:BATTLEBOND)
  species_data.get_evolutions(true).each do |evo| # [new_species, method, parameter, boolean]
    next if evo[3] # Prevolution
	unless $game_switches[DONT_CARE_ABOUT_DEXES]
      if !$player.pokedex.unlocked?(-1)
        if Settings::USE_CURRENT_REGION_DEX
          region = pbGetCurrentRegion
          region = -1 if region >= dexes_count - 1
          next if !pbAllRegionalSpecies(region).include?(evo[0])
        else
          has_dex = false
          $player.pokedex.dexes_count.times do |i|
            dex_list_to_check = (i == $player.pokedex.dexes_count - 1) ? -1 : i
            next if dex_list_to_check == -1
            next if   !$player.pokedex.unlocked?(i)
            if pbAllRegionalSpecies(i).include?(evo[0])
              has_dex = true
              break
            end
          end
          next unless has_dex
        end
	  end
    end
    ret = yield self, evo[0], evo[1], evo[2] # pkmn, new_species, method, parameter
    return ret if ret
  end
  return nil
end