code: public <T> T getValue(String nameSpace, String cellName, Class<T> cellClass) {
          Cell cell = getCellByName(nameSpace, cellName);
          return cell == null ? null : cell.getValue(cellClass);
      }
docs: Returns the casted value of the {@link Cell} (associated to {@code table}) whose name is cellName, or null if
  this Cells object contains no cell whose name is cellName.
  
  @param nameSpace the name of the owning table
  @param cellName  the name of the Cell we want to retrieve from this Cells object.
  @param cellClass the class of the cell's value
  @param <T>       the type of the cell's value
  @return the casted value of the {@link Cell} (associated to {@code table}) whose name is cellName, or null if
  this Cells object contains no cell whose name is cellName