code: public function getInputSpecification()
      {
          return [
              'name'       => $this->getName(),
              'required'   => true,
              'filters'    => [
                  Filter\StringTrim::class    => [
                      'name' => Filter\StringTrim::class
                  ],
                  Filter\StripNewlines::class => [
                      'name' => Filter\StripNewlines::class
                  ]
              ],
              'validators' => [
                  UsernameValidator::class => [
                      'name' => UsernameValidator::class
                  ]
              ]
          ];
      }
docs: Provide default input rules for this element and attaches an password validator.
  
  @return array