@Override
	public int getNumSources(CodeBlock block, TaskMonitor monitor) throws CancelledException {

		if (!(block.getModel() instanceof MultEntSubModel)) {
			throw new IllegalArgumentException();
		}

		return SubroutineSourceReferenceIterator.getNumSources(block, monitor);
	}
@see ghidra.program.model.block.CodeBlockModel#getNumSources(ghidra.program.model.block.CodeBlock, ghidra.util.task.TaskMonitor)
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/block/MultEntSubModel.java