finding sublist

[giampiero mu]

hi everyone

my target is implement a function controlla(string - a binary string-)
that check if there is in a string two equal not overlapping
subsequences at least of length limitem:

my code:

def controlla(test):
#       print test
        limitem=4
	lunghezz=len(test)

        l1=lunghezz-limitem+1
        l2=lunghezz-limitem+1
        f=0

        for ii in range(l1):
                for kk in range(l2):
                        t1=test[ii:ii+limitem]
                        t2=test[kk:kk+limitem]
                        if abs(ii-kk)>=limitem :
                                if t1==t2 :
                                        f=1
                                if f==1 :
                                        break
                                        break
					break
        if f==0 :
                return test
        else:
		return 'no'


the question is: Is there a faster way doing that? I don't know,
changing string into list or array, using map, or module, using
different loop, regular expression,funcional programming , list
comprehensions , sets, different looping techniques, i dont
know.......(!)