set_book_subject_effect

set_book_subject_effect = {
	save_temporary_scope_value_as = {
		name = allow_no_subject_option
		value = $NO_SUBJECT$
	}
	hidden_effect = { #If they haven't specified what they're gonna write about we decide it here (might still leave it up to the sponsor if allow_no_subject_option = yes!)
		$BASE_SCOPE$ = {
			if = {
				limit = {
					NOT = { exists = var:book_subject }
				}
				random_list = { #What do they want to write about?
					1 = {
						modifier = {
							add = 60
							has_education_martial_trigger = yes
						}
						modifier = {
							add = 40
							book_subject_martial_trigger = yes
						}
						modifier = {
							add = { #If they're good you get +, if they're shit you get -
								value = average_skill_rating
								subtract = martial
								multiply = -5
							}
						}
						set_variable = {
							name = book_subject
							value = flag:martial
						}
					}
					1 = {
						modifier = {
							add = 60
							has_education_diplomacy_trigger = yes
						}
						modifier = {
							add = { #If they're good you get +, if they're shit you get -
								value = average_skill_rating
								subtract = diplomacy
								multiply = -5
							}
						}
						set_variable = {
							name = book_subject
							value = flag:diplomacy
						}
					}
					1 = {
						modifier = {
							add = 60
							has_education_stewardship_trigger = yes
						}
						modifier = {
							add = { #If they're good you get +, if they're shit you get -
								value = average_skill_rating
								subtract = stewardship
								multiply = -5
							}
						}
						set_variable = {
							name = book_subject
							value = flag:stewardship
						}
					}
					1 = {
						modifier = {
							add = 60
							has_education_intrigue_trigger = yes
						}
						modifier = {
							add = { #If they're good you get +, if they're shit you get -
								value = average_skill_rating
								subtract = intrigue
								multiply = -5
							}
						}
						set_variable = {
							name = book_subject
							value = flag:intrigue
						}
					}
					1 = {
						modifier = {
							add = 60
							has_education_learning_trigger = yes
						}
						modifier = {
							add = { #If they're good you get +, if they're shit you get -
								value = average_skill_rating
								subtract = learning
								multiply = -5
							}
						}
						set_variable = {
							name = book_subject
							value = flag:learning
						}
					}
					1 = {
						modifier = {
							add = 50
							book_subject_medicine_trigger = yes
						}
						modifier = {
							add = 20
							is_witch_trigger = yes
						}
						modifier = {
							add = {
								value = learning
								multiply = 2
							}
						}
						ai_value_modifier = {
							ai_rationality = 0.25
						}
						set_variable = {

As written in game/common/scripted_effects/01_ep1_court_artifact_creation_effects.txt.