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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 _nat_rules_for_internet_access(self, acl_no, network, netmask, inner_itfc, outer_itfc, vrf_name):
 """Configure the NAT rules for an internal network. Configuring NAT rules in the ASR1k is a three step process. First create an ACL for the IP range of the internal network. Then enable dynamic source NATing on the external interface of the ASR1k for this ACL and VRF of the neutron router. Finally enable NAT on the interfaces of the ASR1k where the internal and external networks are connected. :param acl_no: ACL number of the internal network. :param network: internal network :param netmask: netmask of the internal network. :param inner_itfc: (name of) interface connected to the internal network :param outer_itfc: (name of) interface connected to the external network :param vrf_name: VRF corresponding to this virtual router :return: True if configuration succeeded :raises: networking_cisco.plugins.cisco.cfg_agent.cfg_exceptions. IOSXEConfigException """

        acl_present = self._check_acl(acl_no, network, netmask)
        if not acl_present:
            conf_str = snippets.CREATE_ACL % (acl_no, network, netmask)
            self._edit_running_config(conf_str, 'CREATE_ACL')

        pool_name = "%s_nat_pool" % vrf_name
        conf_str = asr1k_snippets.SET_DYN_SRC_TRL_POOL % (acl_no, pool_name,
                                                          vrf_name)
        try:
            self._edit_running_config(conf_str, 'SET_DYN_SRC_TRL_POOL')
        except Exception as dyn_nat_e:
            LOG.info("Ignore exception for SET_DYN_SRC_TRL_POOL: %s. "
                     "The config seems to be applied properly but netconf "
                     "seems to report an error.", dyn_nat_e)

        conf_str = snippets.SET_NAT % (inner_itfc, 'inside')
        self._edit_running_config(conf_str, 'SET_NAT')

        conf_str = snippets.SET_NAT % (outer_itfc, 'outside')
        self._edit_running_config(conf_str, 'SET_NAT')