code: public function configure(array $configuration = null)
      {
          parent::configure($configuration);
  
          static $reprToTokenMap = [
              'break' => T_BREAK,
              'case' => T_CASE,
              'continue' => T_CONTINUE,
              'curly_brace_block' => '{',
              'default' => T_DEFAULT,
              'extra' => T_WHITESPACE,
              'parenthesis_brace_block' => '(',
              'return' => T_RETURN,
              'square_brace_block' => CT::T_ARRAY_SQUARE_BRACE_OPEN,
              'switch' => T_SWITCH,
              'throw' => T_THROW,
              'use' => T_USE,
              'use_trait' => CT::T_USE_TRAIT,
          ];
  
          static $tokenKindCallbackMap = [
              T_BREAK => 'fixAfterToken',
              T_CASE => 'fixAfterToken',
              T_CONTINUE => 'fixAfterToken',
              T_DEFAULT => 'fixAfterToken',
              T_RETURN => 'fixAfterToken',
              T_SWITCH => 'fixAfterToken',
              T_THROW => 'fixAfterToken',
              T_USE => 'removeBetweenUse',
              T_WHITESPACE => 'removeMultipleBlankLines',
              CT::T_USE_TRAIT => 'removeBetweenUse',
              CT::T_ARRAY_SQUARE_BRACE_OPEN => 'fixStructureOpenCloseIfMultiLine', // typeless '[' tokens should not be fixed (too rare)
          ];
  
          static $tokenEqualsMap = [
              '{' => 'fixStructureOpenCloseIfMultiLine', // i.e. not: CT::T_ARRAY_INDEX_CURLY_BRACE_OPEN
              '(' => 'fixStructureOpenCloseIfMultiLine', // i.e. not: CT::T_BRACE_CLASS_INSTANTIATION_OPEN
          ];
  
          $tokensAssoc = array_flip(array_intersect_key($reprToTokenMap, array_flip($this->configuration['tokens'])));
  
          $this->tokenKindCallbackMap = array_intersect_key($tokenKindCallbackMap, $tokensAssoc);
          $this->tokenEqualsMap = array_intersect_key($tokenEqualsMap, $tokensAssoc);
      }
docs: {@inheritdoc}