Bug 184762 BIRT Model - Enhancments to the level defintion
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ModuleHandle.java
* @return A handle for working with the data sources.
	 */
	public SlotHandle getDataSources( )
	{
		return getSlot( DATA_SOURCE_SLOT );
	}
	/**
	 * Returns the default units for the design. These are the units that are
	 * used for dimensions that don't explicitly specify units.
	 * 
	 * @return the default units for the design.
	 * @see org.eclipse.birt.report.model.api.metadata.DimensionValue
	 */
	public String getDefaultUnits( )
	{
		return module.getUnits( );
	}
	/**
	 * Sets the default units for the design. These are the units that are used
	 * for dimensions that don't explicitly specify units.
	 * <p>
	 * 
	 * For a report design, it allows the following constants that defined in
	 * <code>{@link org.eclipse.birt.report.model.api.elements.DesignChoiceConstants}</code>:
	 * <ul>
	 * <li><code>UNITS_IN</code></li>
	 * <li><code>UNITS_CM</code></li>
	 * <li><code>UNITS_MM</code></li>
	 * <li><code>UNITS_PT</code></li>
	 * </ul>