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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 _set_return_address(self, state, ret_addr):
 """ Set the return address of the current state to a specific address. We assume we are at the beginning of a function, or in other words, we are about to execute the very first instruction of the function. :param SimState state: The program state :param int ret_addr: The return address :return: None """


        # TODO: the following code is totally untested other than X86 and AMD64. Don't freak out if you find bugs :)
        # TODO: Test it

        ret_bvv = state.solver.BVV(ret_addr, self.project.arch.bits)

        if self.project.arch.name in ('X86', 'AMD64'):
            state.stack_push(ret_bvv)
        elif is_arm_arch(self.project.arch):
            state.regs.lr = ret_bvv
        elif self.project.arch.name in ('MIPS32', 'MIPS64'):
            state.regs.ra = ret_bvv
        elif self.project.arch.name in ('PPC32', 'PPC64'):
            state.regs.lr = ret_bvv
        else:
            l.warning('Return address cannot be set for architecture %s. Please add corresponding logic to '
                      'VFG._set_return_address().', self.project.arch.name
                      )