You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: MetaDataTagsClass.m
    path of file: ./repos/fieldtrip/external/homer3
    
    the code of the file until where you have to start completion: classdef MetaDataTagsClass
    
function b = IsValid(obj)
            b = false;
            
            % Use latest required fields to determine if we're loading old
            % metaDataTag format version of SNIRF spec
            if ~isproperty(obj.tags, 'FrequencyUnit')
                return;
            end