code: public function getDefinition()
      {
          $versionSpecification = new VersionSpecification(70000);
  
          return new FixerDefinition(
              'There should be one or no space before colon, and one space after it in return type declarations, according to configuration.',
              [
                  new VersionSpecificCodeSample(
                      "<?php\nfunction foo(int \$a):string {};\n",
                      $versionSpecification
                  ),
                  new VersionSpecificCodeSample(
                      "<?php\nfunction foo(int \$a):string {};\n",
                      $versionSpecification,
                      ['space_before' => 'none']
                  ),
                  new VersionSpecificCodeSample(
                      "<?php\nfunction foo(int \$a):string {};\n",
                      $versionSpecification,
                      ['space_before' => 'one']
                  ),
              ],
              'Rule is applied only in a PHP 7+ environment.'
          );
      }
docs: {@inheritdoc}