def using_single_table_inheritance?(klass, record)
      inheritance_column = klass.inheritance_column
      record[inheritance_column].present? && record.has_attribute?(inheritance_column)
    end
def using_single_table_inheritance?(klass, record)
      inheritance_column = klass.inheritance_column
      record[inheritance_column].present? && record.has_attribute?(inheritance_column)
    end
Backport for Rails 3.2