Write a function go/3 as described above.

You should use the functions above for this.

The go/3 function will be called by a new version of islegal/2. Here's the old one:

islegal(Str) :? string_chars(Str,Cs), start(State), go(State,Cs).

Here's the new one:

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%%CONSULTislegal(F,S) :- string_chars(S,Cs), getinitial(F,I), go(F,I,Cs).

(Make sure to "run" that cell so you can use it.)

Here is the old go/2 function.

go(State,[]) :? final(State), !.go(State,[C|Str]) :? arc(State,C,Otherstate), go(Otherstate,Str).

Now write go/3.

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%%CONSULT%Your code here

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islegal( fsa(initial(1),final([3]),arcs([arc(1,a,2),arc(2,b,3)])), "ab").

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islegal( fsa(initial(1),final([3,1]),arcs([arc(1,a,2),arc(2,b,3)])), "").

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+islegal( fsa(initial(1),final([3]),arcs([arc(1,a,2),arc(2,b,3)])), "abc").