@classmethod
    def isEmail(cls, s):
        if not s:                                                    # Some extra safety
            return False
        try:
            split = re.findall(cls.EMAILPATTERN, s)[0]
        except IndexError:
            #print '[%s] Wrong email pattern' % s                    # Totally wrong pattern
            return False
            
        if len(split) != 2:
            #print '[%s] Wrong @ pattern' % s
            return False
        user, domain = split

        for c in user:                                                # Test user name characters on > 127
            if ord(c) > 127:
                #print '[%s] User character > 127' % user
                return False
        for c in domain:
            if ord(c) > 127:                                        # Test domain name characters on > 127
                #print '[%s] Domain character > 127' % user
                return False

        u1 = re.findall(cls.QUOTEDUSERPATTERN, user)
        u2 = re.findall(cls.USERPATTERN, user)
        if not (u1 or u2):
            #print '[%s] Wrong user pattern' % user
            return False
            
        
        ip = re.findall(cls.IPPATTERN, domain)                        # Test on ip number and domain name
        if ip:                                                        # Test if values in ip address are valid
            for t in ip[0]:
                v = int(t)
                if not (0 <= v <= 255):
                    #print '[%s] Not within 0-255 range' % domain    # Values not within 0-255 range
                    return False
                    
        d = re.findall(cls.DOMAINPATTERN, domain)        
        if not (ip or d):
            #print '[%s] Wrong domain pattern' % user
            return False
                
        return True
assuming that we know element N and we want to get element N-M
dataset/ETHPy150Open petrvanblokland/Xierpa3/xierpa3/toolbox/parsers/validator.py/Validator.isEmail--crossover with--dataset/ETHPy150Open tschellenbach/Stream-Framework/stream_framework/tests/feeds/base.py/TestBaseFeed.test_feed_pagination