class RuboCop::Cop::Rails::SaveBang

def check_assignment(assignment)
  node = right_assignment_node(assignment)
  return unless node
  return unless CREATE_PERSIST_METHODS.include?(node.method_name)
  return unless expected_signature?(node)
  return if persisted_referenced?(assignment)
  add_offense(node, :selector,
              format(CREATE_MSG,
                     "#{node.method_name}!",
                     node.method_name.to_s,
                     node.method_name.to_s))
end