code: def validate_for(field, value)
        @messages = []
        key = field.to_sym
        result = true
        each_validation_for(key) do |validation|
          validation.each_pair do |validation_type, setting|
            method = validation_method(validation_type)
            if self.respond_to? method
              value.strip! if value.is_a?(String)
              result &&= self.send(method, field, value, setting)
            end
          end
        end
        result
      end
docs: Validates an arbitrary string against a specific field's validators.
   Useful before setting the value of a model's field. I.e., you get data
   from a form, do a <tt>validate_for(:my_field, that_data)</tt> and
   if it succeeds, you do <tt>obj.my_field = that_data</tt>.