public Date getDate(String nameSpace, String cellName) {
        return getValue(nameSpace, cellName, Date.class);
    }
public Date getDate ( String nameSpace , String cellName ) { return getValue ( nameSpace , cellName , Date . class ) ; }
Returns the {@code Date} value of the {@link Cell} (associated to {@code table}) whose name iscellName, 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.
@return the {@code Date} 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