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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 token_network_connect( self, registry_address: PaymentNetworkID, token_address: TokenAddress, funds: TokenAmount, initial_channel_target: int = 3, joinable_funds_target: float = 0.4, ) -> None: """ Automatically maintain channels open for the given token network. Args: token_address: the ERC20 token network to connect to. funds: the amount of funds that can be used by the ConnectionMananger. initial_channel_target: number of channels to open proactively. joinable_funds_target: fraction of the funds that will be used to join channels opened by other participants. """

        if not is_binary_address(registry_address):
            raise InvalidAddress('registry_address must be a valid address in binary')
        if not is_binary_address(token_address):
            raise InvalidAddress('token_address must be a valid address in binary')

        token_network_identifier = views.get_token_network_identifier_by_token_address(
            chain_state=views.state_from_raiden(self.raiden),
            payment_network_id=registry_address,
            token_address=token_address,
        )

        connection_manager = self.raiden.connection_manager_for_token_network(
            token_network_identifier,
        )

        has_enough_reserve, estimated_required_reserve = has_enough_gas_reserve(
            raiden=self.raiden,
            channels_to_open=initial_channel_target,
        )

        if not has_enough_reserve:
            raise InsufficientGasReserve((
                'The account balance is below the estimated amount necessary to '
                'finish the lifecycles of all active channels. A balance of at '
                f'least {estimated_required_reserve} wei is required.'
            ))

        connection_manager.connect(
            funds=funds,
            initial_channel_target=initial_channel_target,
            joinable_funds_target=joinable_funds_target,
        )