def validate_children
      child_associations.each do |collection|
        if collection.dirty?
          collection.each do |child|
            unless child.valid?
              relationship_errors = (errors[collection.relationship.name] ||= [])
              unless relationship_errors.include?(child.errors)
                relationship_errors << child.errors
              end
            end
          end
        end
      end
    end
def validate_children
      child_associations.each do |collection|
        if collection.dirty?
          collection.each do |child|
            unless child.valid?
              relationship_errors = (errors[collection.relationship.name] ||= [])
              unless relationship_errors.include?(child.errors)
                relationship_errors << child.errors
              end
            end
          end
        end
      end
    end
Run validations on the associated child resources

 @api semipublic