DataType getDataType(long dataTypeId) {
		DataType dataType = dataManager.getDataType(dataTypeId);
		if (dataType == null || dataType.isDeleted()) {
			return DataType.DEFAULT;
		}
		if (dataType.getLength() > 0) {
			// Return variable - although it could be too big
			return dataType;
		}
		if (dataType instanceof Pointer) {
			return program.getDataTypeManager().getPointer(((Pointer) dataType).getDataType());
		}
		return program.getDataTypeManager().getPointer(dataType);
	}
Copy old function into programs current function manager.
@param function existing function
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/oldfunction/OldFunctionManager.java