src/transformers/generation/beam_constraints.py/ConstraintListState/__init__
class ConstraintListState:    def __init__(self, constraints: List[Constraint]):
        self.constraints = constraints

        # max # of steps required to fulfill a given constraint
        self.max_seqlen = max([c.seqlen for c in constraints])
        self.n_constraints = len(constraints)
        self.completed = False

        self.init_state()