set_duchies_to_attack_effect

set_duchies_to_attack_effect = {
	while = {
		count = 20 #as for tgp France holds the record for the most duchies with 17
		limit = {
			list_size:duchies_to_attack > 0
		}
		# Assign the project's location Duchy as the mandatory contribution
		if = {
			limit = {
				NOT = { exists = scope:grand_campaign_project.var:attack_1 }
			}
			random_in_list = {
				list = duchies_to_attack
				limit = {
					this = scope:grand_campaign_project.great_project_location.duchy
				}
				set_duchies_to_attack_variable_effect = {
					VALUE = 1
				}
			}
		}
		# Otherwise pick the smallest duchy and assign it the furthest possible variable
		ordered_in_list = {
			list = duchies_to_attack
			order_by = {
				value = holder.realm_size
				multiply = -1
			}
			limit = {
				this != scope:grand_campaign_project.great_project_location.duchy
			}
			switch = {
				trigger = list_size:duchies_to_attack
				1 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 2
					}
				}
				2 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 3
					}
				}
				3 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 4
					}
				}
				4 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 5
					}
				}
				5 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 6
					}
				}
				6 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 7
					}
				}
				7 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 8
					}
				}
				8 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 9
					}
				}
				9 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 10
					}
				}
				10 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 11
					}
				}
				11 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 12
					}
				}
				12 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 13
					}
				}
				13 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 14
					}
				}
				14 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 15
					}
				}
				15 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 16
					}
				}
				16 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 17
					}
				}
				17 = {
					set_duchies_to_attack_variable_effect = {
						VALUE = 18
					}
				}
				18 = {
					set_duchies_to_attack_variable_effect = {

As written in game/common/scripted_effects/10_dlc_tgp_scripted_effects.txt.