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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
 Transducers
Transducers, also called k-tape automata, are finite state machines where transitions are labeled on several tapes. The labelset of a transducer is a cartesian product of the labelsets of each tape
Step1:  Now we can define a transducer that will transform every a into b, and keep the rest of the letters. When writing the expression, to delimit the labels (a letter for each tape), we have to use simple quotes.
Step2:  Similarly, it is possible to define weighted transducers, as for weighted automata
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Python Code:
import vcsn
ctx = vcsn.context("lat<lal_char(abc), lal_char(abc)>, b")
ctx
Explanation: Transducers
Transducers, also called k-tape automata, are finite state machines where transitions are labeled on several tapes. The labelset of a transducer is a cartesian product of the labelsets of each tape: $L = L_1 \times \dots \times L_k$.
Usually, it is common to manipulate 2-tape transducers, and to consider one as the input tape, and the other as the output tape. For example, we can define a 2-tape transducer with the first tape accepting letters in [a-c], and the same for the second tape:
End of explanation
r = ctx.expression("(a|b+b|b+c|c)*")
r
r.automaton()
Explanation: Now we can define a transducer that will transform every a into b, and keep the rest of the letters. When writing the expression, to delimit the labels (a letter for each tape), we have to use simple quotes.
End of explanation
import vcsn
ctxw = vcsn.context("lat<lan_char(ab), lan_char(xy)>, z")
ctxw
r = ctxw.expression("(a|x)*((a|y)(b|x))*(b|y)*")
r
r.thompson()
Explanation: Similarly, it is possible to define weighted transducers, as for weighted automata:
End of explanation
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