code: public function extractCellRange(&$pRange = 'A1', Worksheet $pSheet = null, $resetLog = true)
      {
          // Return value
          $returnValue = [];
  
          if ($pSheet !== null) {
              $pSheetName = $pSheet->getTitle();
              if (strpos($pRange, '!') !== false) {
                  list($pSheetName, $pRange) = Worksheet::extractSheetTitle($pRange, true);
                  $pSheet = $this->spreadsheet->getSheetByName($pSheetName);
              }
  
              // Extract range
              $aReferences = Coordinate::extractAllCellReferencesInRange($pRange);
              $pRange = $pSheetName . '!' . $pRange;
              if (!isset($aReferences[1])) {
                  //    Single cell in range
                  sscanf($aReferences[0], '%[A-Z]%d', $currentCol, $currentRow);
                  if ($pSheet->cellExists($aReferences[0])) {
                      $returnValue[$currentRow][$currentCol] = $pSheet->getCell($aReferences[0])->getCalculatedValue($resetLog);
                  } else {
                      $returnValue[$currentRow][$currentCol] = null;
                  }
              } else {
                  // Extract cell data for all cells in the range
                  foreach ($aReferences as $reference) {
                      // Extract range
                      sscanf($reference, '%[A-Z]%d', $currentCol, $currentRow);
                      if ($pSheet->cellExists($reference)) {
                          $returnValue[$currentRow][$currentCol] = $pSheet->getCell($reference)->getCalculatedValue($resetLog);
                      } else {
                          $returnValue[$currentRow][$currentCol] = null;
                      }
                  }
              }
          }
  
          return $returnValue;
      }
docs: Extract range values.
  
  @param string &$pRange String based range representation
  @param Worksheet $pSheet Worksheet
  @param bool $resetLog Flag indicating whether calculation log should be reset or not
  
  @return mixed Array of values in range if range contains more than one element. Otherwise, a single value is returned.