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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def has_true(self, e, extra_constraints=(), solver=None, model_callback=None):
 #pylint:disable=unused-argument """ Should return True if `e` can possible be True. :param e: The AST. :param extra_constraints: Extra constraints (as ASTs) to add to the solver for this solve. :param solver: A solver, for backends that require it. :param model_callback: a function that will be executed with recovered models (if any) :return: A boolean """


        #if self._solver_required and solver is None:
        #   raise BackendError("%s requires a solver for evaluation" % self.__class__.__name__)

        return self._has_true(self.convert(e), extra_constraints=extra_constraints, solver=solver, model_callback=model_callback)