evaluate_condition (ActiveRecord::Validations::ClassMethods)

    # File lib/active_record/validations.rb, line 348
          def evaluate_condition(condition, record)
            case condition
              when Symbol; record.send(condition)
              when String; eval(condition, record.send(:binding))
              else
                if condition_block?(condition)
                  condition.call(record)
                else
                  raise(
                    ActiveRecordError,
                    "Validations need to be either a symbol, string (to be eval'ed), proc/method, or " +
                    "class implementing a static validation method"
                  )
                end
              end
          end