code: func nullableBool(schema *spec.Schema, isRequired bool) bool {
  	if nullable := nullableExtension(schema.Extensions); nullable != nil {
  		return *nullable
  	}
  	required := isRequired && schema.Default == nil && !schema.ReadOnly
  	optional := !isRequired && (schema.Default != nil || schema.ReadOnly)
  
  	return required || optional
  }
docs: // nullableBool makes a boolean a pointer when we want to distinguish the zero value from no value set.
  // This is the case when:
  // - a x-nullable extension says so in the spec
  // - it is **not** a read-only property
  // - it is a required property
  // - it has a default value