code: private function fixFunction(Tokens $tokens, $startFunctionIndex)
      {
          $endFunctionIndex = $tokens->findBlockEnd(Tokens::BLOCK_TYPE_PARENTHESIS_BRACE, $startFunctionIndex);
  
          $isMultiline = false;
  
          $firstWhitespaceIndex = $this->findWhitespaceIndexAfterParenthesis($tokens, $startFunctionIndex, $endFunctionIndex);
          $lastWhitespaceIndex = $this->findWhitespaceIndexAfterParenthesis($tokens, $endFunctionIndex, $startFunctionIndex);
  
          foreach ([$firstWhitespaceIndex, $lastWhitespaceIndex] as $index) {
              if (null === $index || !Preg::match('/\R/', $tokens[$index]->getContent())) {
                  continue;
              }
  
              if ('ensure_single_line' !== $this->configuration['on_multiline']) {
                  $isMultiline = true;
  
                  continue;
              }
  
              $newLinesRemoved = $this->ensureSingleLine($tokens, $index);
              if (!$newLinesRemoved) {
                  $isMultiline = true;
              }
          }
  
          for ($index = $endFunctionIndex - 1; $index > $startFunctionIndex; --$index) {
              $token = $tokens[$index];
  
              if ($token->equals(')')) {
                  $index = $tokens->findBlockStart(Tokens::BLOCK_TYPE_PARENTHESIS_BRACE, $index);
  
                  continue;
              }
  
              if ($token->isGivenKind(CT::T_ARRAY_SQUARE_BRACE_CLOSE)) {
                  $index = $tokens->findBlockStart(Tokens::BLOCK_TYPE_ARRAY_SQUARE_BRACE, $index);
  
                  continue;
              }
  
              if ($token->equals('}')) {
                  $index = $tokens->findBlockStart(Tokens::BLOCK_TYPE_CURLY_BRACE, $index);
  
                  continue;
              }
  
              if ($token->equals(',')) {
                  $this->fixSpace2($tokens, $index);
                  if (!$isMultiline && $this->isNewline($tokens[$index + 1])) {
                      $isMultiline = true;
  
                      break;
                  }
              }
          }
  
          return $isMultiline;
      }
docs: Fix arguments spacing for given function.
  
  @param Tokens $tokens             Tokens to handle
  @param int    $startFunctionIndex Start parenthesis position
  
  @return bool whether the function is multiline