code: public Cell getCellByName(String cellName) {
  
          Set<String> keys = cells.keySet();
          for (String key : keys) {
              List<Cell> cellList = cells.get(key);
              for (Cell c : cellList) {
                  if (c.getCellName().equals(cellName)) {
                      return c;
                  }
              }
  
          }
          return null;
      }
docs: Returns the Cell (associated to the default table) whose name is <i>cellName</i>, or null if this Cells object
  contains no cell whose name is cellName.
  
  @param cellName the name of the Cell we want to retrieve from this Cells object.
  @return the Cell whose name is cellName contained in this Cells object. null if no cell named cellName is
  present.