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

		// get the instruction before this block
		//    if it is contiguous and falls through, then has at least 1 source
		// get the symbol at the start address
		//    add the number of references to the count

		if (block == null) {
			return 0;
		}

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

		return SimpleSourceReferenceIterator.getNumSources(block, followIndirectFlows, monitor);
	}
Get number of source blocks flowing into this block

@param block code block to get the source iterator for.
@param monitor task monitor which allows user to cancel operation.
@throws CancelledException if the monitor cancels the operation.
@deprecated this method should be avoided since it repeats the work of the getSources iterator
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/block/SimpleBlockModel.java