@Override
	public FunctionIterator getFunctionsNoStubs(AddressSetView asv, boolean forward) {
		return new FunctionFilteredIterator(new FunctionIteratorDB(asv, forward));
	}
Get the function with the given key.
@param key ID of the function; ID is obtained by calling
Function.getID()
@return null if there is no function with the given key
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/function/FunctionManagerDB.java