class ActiveRecord::Coders::ColumnSerializer

def assert_valid_value(object, action:)

Public because it's called by Type::Serialized
def assert_valid_value(object, action:)
  unless object.nil? || object_class === object
    raise SerializationTypeMismatch,
      "can't #{action} `#{@attr_name}`: was supposed to be a #{object_class}, but was a #{object.class}. -- #{object.inspect}"
  end
end