$(23)$ Let $\backslash$Sigma $=\{$a$,$ b$\}.$ Determine all possible DFAs having exactly two states, and briefly describe

$($in English$)$ what language each one recognizes. You might find it helpful to write a program

to generate all of the DFAs. For DFAs, if neither is final the language is empty, and if both

are final the language is $\backslash$Sigma $?,$ so you need only consider the cases when there is exactly one

final state.