diff --git a/firewall.py b/firewall.py
index 9063a72..a87b4c8 100755
--- a/firewall.py
+++ b/firewall.py
@@ -64,13 +64,9 @@ class PortRange(str):
             start, end = v.split("..")
         except AttributeError:
             parse_obj_as(Port, v)  # This is the expected error
-            raise ValueError(
-                "invalid port range: must be in the form start..end"
-            )
+            raise ValueError("invalid port range: must be in the form start..end")
         except ValueError:
-            raise ValueError(
-                "invalid port range: must be in the form start..end"
-            )
+            raise ValueError("invalid port range: must be in the form start..end")
 
         start, end = parse_obj_as(Port, start), parse_obj_as(Port, end)
         if start > end:
@@ -120,10 +116,10 @@ class TcpProtocol(RestrictiveBaseModel):
     dport: AutoSet[Port | PortRange] = AutoSet()
     sport: AutoSet[Port | PortRange] = AutoSet()
 
-    def __bool__(self):
+    def __bool__(self) -> bool:
         return bool(self.sport or self.dport)
 
-    def __getitem__(self, key):
+    def __getitem__(self, key: str) -> set[Port | PortRange]:
         return getattr(self, key)
 
 
@@ -131,10 +127,10 @@ class UdpProtocol(RestrictiveBaseModel):
     dport: AutoSet[Port | PortRange] = AutoSet()
     sport: AutoSet[Port | PortRange] = AutoSet()
 
-    def __bool__(self):
+    def __bool__(self) -> bool:
         return bool(self.sport or self.dport)
 
-    def __getitem__(self, key):
+    def __getitem__(self, key: str) -> set[Port | PortRange]:
         return getattr(self, key)
 
 
@@ -145,7 +141,7 @@ class Protocols(RestrictiveBaseModel):
     udp: UdpProtocol = UdpProtocol()
     vrrp: bool = False
 
-    def __getitem__(self, key):
+    def __getitem__(self, key: str) -> bool | TcpProtocol | UdpProtocol:
         return getattr(self, key)
 
 
@@ -159,9 +155,9 @@ class Rule(RestrictiveBaseModel):
 
 
 class Filter(RestrictiveBaseModel):
-    input: list[Rule] = list()
-    output: list[Rule] = list()
-    forward: list[Rule] = list()
+    input: list[Rule] = []
+    output: list[Rule] = []
+    forward: list[Rule] = []
 
 
 # Nat
@@ -177,11 +173,11 @@ class Nat(RestrictiveBaseModel):
 
 # Root model
 class Firewall(RestrictiveBaseModel):
-    zones: dict[ZoneName, ZoneEntry] = dict()
+    zones: dict[ZoneName, ZoneEntry] = {}
     blacklist: Blacklist = Blacklist()
     reverse_path_filter: ReversePathFilter = ReversePathFilter()
     filter: Filter = Filter()
-    nat: list[Nat] = list()
+    nat: list[Nat] = []
 
 
 # ==========[ ZONES ]===========================================================
@@ -191,7 +187,7 @@ class ZoneFile(RestrictiveBaseModel):
     __root__: AutoSet[IPvAnyNetwork]
 
 
-@dataclass
+@dataclass(eq=True, frozen=True)
 class ResolvedZone:
     addrs: set[IPvAnyNetwork]
     negate: bool
@@ -206,9 +202,7 @@ def resolve_zones(yaml_zones: dict[ZoneName, ZoneEntry]) -> Zones:
 
     for name in TopologicalSorter(zone_graph).static_order():
         if yaml_zones[name].addrs:
-            zones[name] = ResolvedZone(
-                yaml_zones[name].addrs, yaml_zones[name].negate
-            )
+            zones[name] = ResolvedZone(yaml_zones[name].addrs, yaml_zones[name].negate)
 
         elif yaml_zones[name].file is not None:
             with open(yaml_zones[name].file, "r") as file:
@@ -219,9 +213,7 @@ def resolve_zones(yaml_zones: dict[ZoneName, ZoneEntry]) -> Zones:
                         f"YAML parsing of the included file '{yaml_zones[name].file}' failed: {e}"
                     )
 
-            zones[name] = ResolvedZone(
-                yaml_addrs.__root__, yaml_zones[name].negate
-            )
+            zones[name] = ResolvedZone(yaml_addrs.__root__, yaml_zones[name].negate)
 
         elif yaml_zones[name].zones:
             addrs: set[IPvAnyNetwork] = set()
@@ -238,7 +230,7 @@ def resolve_zones(yaml_zones: dict[ZoneName, ZoneEntry]) -> Zones:
 
 
 def split_v4_v6(
-    addrs: Iterator[IPvAnyNetwork]
+    addrs: Iterator[IPvAnyNetwork],
 ) -> tuple[set[IPv4Network], set[IPv6Network]]:
     v4, v6 = set(), set()
 
@@ -258,27 +250,43 @@ def zones_into_ip(
     zones: Zones,
     allow_negate: bool = True,
 ) -> Iterator[IPvAnyNetwork]:
+    for element in elements:
+        match element:
+            case ZoneName():
+                try:
+                    zone = zones[element]
+                except KeyError:
+                    raise ValueError(f"zone '{element}' does not exist")
+
+                if not allow_negate and zone.negate:
+                    raise ValueError(f"zone '{element}' cannot be negated")
 
-    elements_zones = {zones[e] for e in elements if isinstance(e, ZoneName)}
-    elements_addrs = {e for e in elements if isinstance(e, IPvAnyNetwork)}
+                yield from zone.addrs
 
-    negate = any(z.negate for z in elements_zones)
+            case IPv4Network() | IPv6Network():
+                yield element
 
-    if negate:
-        if not allow_negate:
-            raise ValueError("can't negate zones")
-        if len(elements_zones) > 1:
-            raise ValueError("can't have more than one negated zone")
-        if len(elements_zones) > 1 or elements_addrs:
-            raise ValueError("can't mix negated zones and inline networks")
+    # TODO: Jeltz
+    # elements_zones = {zones[e] for e in elements if isinstance(e, ZoneName)}
+    # elements_addrs = {e for e in elements if isinstance(e, IPvAnyNetwork)}
 
-    if negate and not allow_negate:
-    elif negate and elements_addrs:
+    # negate = any(z.negate for z in elements_zones)
 
-    yield from elements_addrs
+    # if negate:
+    #     if not allow_negate:
+    #         raise ValueError("can't negate zones")
+    #     if len(elements_zones) > 1:
+    #         raise ValueError("can't have more than one negated zone")
+    #     if len(elements_zones) > 1 or elements_addrs:
+    #         raise ValueError("can't mix negated zones and inline networks")
 
-    for zone in elements_zones:
-        yield from zone.addrs
+    # if negate and not allow_negate:
+    # elif negate and elements_addrs:
+
+    # yield from elements_addrs
+
+    # for zone in elements_zones:
+    #     yield from zone.addrs
 
 
 def parse_blacklist(blacklist: Blacklist, zones: Zones) -> nft.Table:
@@ -340,9 +348,7 @@ def parse_reverse_path_filter(rpf: ReversePathFilter) -> nft.Table:
         priority=-300,
     )
 
-    rule_iifname = nft.Match(
-        op="!=", left=nft.Meta("iifname"), right="@disabled_ifs"
-    )
+    rule_iifname = nft.Match(op="!=", left=nft.Meta("iifname"), right="@disabled_ifs")
 
     rule_fib = nft.Match(
         op="==",
@@ -370,38 +376,37 @@ def parse_reverse_path_filter(rpf: ReversePathFilter) -> nft.Table:
 
 
 class InetRuleBuilder:
-    def __init__(self):
-        self._v4 = []
-        self._v6 = []
+    def __init__(self) -> None:
+        self._v4: list[nft.Statement] | None = []
+        self._v6: list[nft.Statement] | None = []
 
-    def add_any(self, match):
-        self.add_v4(match)
-        self.add_v6(match)
+    def add_any(self, stmt: nft.Statement) -> None:
+        self.add_v4(stmt)
+        self.add_v6(stmt)
 
-    def add_v4(self, match):
+    def add_v4(self, stmt: nft.Statement) -> None:
         if self._v4 is not None:
-            self._v4.append(match)
+            self._v4.append(stmt)
 
-    def add_v6(self, match):
+    def add_v6(self, stmt: nft.Statement) -> None:
         if self._v6 is not None:
-            self._v6.append(match)
+            self._v6.append(stmt)
 
-    def disable_v4(self):
+    def disable_v4(self) -> None:
         self._v4 = None
 
-    def disable_v6(self):
+    def disable_v6(self) -> None:
         self._v6 = None
 
     @property
-    def rules(self):
-        print(self._v4)
+    def rules(self) -> Iterator[nft.Rule]:
         if self._v4 is not None:
             yield nft.Rule(self._v4)
         if self._v6 is not None and self._v6 != self._v4:
             yield nft.Rule(self._v6)
 
 
-def parse_filter_rule(rule: Rule, zones: Zones) -> list[nft.Rule]:
+def parse_filter_rule(rule: Rule, zones: Zones) -> Iterator[nft.Rule]:
     builder = InetRuleBuilder()
 
     for attr in ("iif", "oif"):
@@ -416,9 +421,7 @@ def parse_filter_rule(rule: Rule, zones: Zones) -> list[nft.Rule]:
 
     for attr, field in (("src", "saddr"), ("dst", "daddr")):
         if getattr(rule, attr, None) is not None:
-            addr_v4, addr_v6 = split_v4_v6(
-                zones_into_ip(getattr(rule, attr), zones)
-            )
+            addr_v4, addr_v6 = split_v4_v6(zones_into_ip(getattr(rule, attr), zones))
 
             if addr_v4:
                 builder.add_v4(
@@ -449,12 +452,8 @@ def parse_filter_rule(rule: Rule, zones: Zones) -> list[nft.Rule]:
         "tcp": ("tcp", "tcp"),
         "udp": ("udp", "udp"),
     }
-    protos_v4 = {
-        v for p, (v, _) in protos.items() if getattr(rule.protocols, p)
-    }
-    protos_v6 = {
-        v for p, (_, v) in protos.items() if getattr(rule.protocols, p)
-    }
+    protos_v4 = {v for p, (v, _) in protos.items() if getattr(rule.protocols, p)}
+    protos_v6 = {v for p, (_, v) in protos.items() if getattr(rule.protocols, p)}
 
     if protos_v4:
         builder.add_v4(
@@ -497,9 +496,7 @@ def parse_filter_rule(rule: Rule, zones: Zones) -> list[nft.Rule]:
     return builder.rules
 
 
-def parse_filter_rules(
-    hook: str, rules: list[Rule], zones: Zones
-) -> nft.Chain:
+def parse_filter_rules(hook: str, rules: list[Rule], zones: Zones) -> nft.Chain:
     chain = nft.Chain(
         name=hook,
         type="filter",
diff --git a/nft.py b/nft.py
index 2f03cb5..b6dd486 100644
--- a/nft.py
+++ b/nft.py
@@ -1,7 +1,7 @@
 from dataclasses import dataclass, field
 from itertools import chain
 from ipaddress import IPv4Network, IPv6Network
-from typing import Any, Generic, TypeVar
+from typing import Any, Generic, TypeVar, get_args
 
 T = TypeVar("T")
 JsonNftables = dict[str, Any]
@@ -11,6 +11,9 @@ def flatten(l: list[list[T]]) -> list[T]:
     return list(chain.from_iterable(l))
 
 
+Immediate = int | str | bool | set | range | IPv4Network | IPv6Network
+
+
 @dataclass
 class Ct:
     key: str
@@ -45,11 +48,13 @@ class Payload:
         return {"payload": {"protocol": self.protocol, "field": self.field}}
 
 
-Immediate = int | str | bool | range | IPv4Network | IPv6Network
+Expression = Ct | Fib | Immediate | Meta | Payload
 
-def imm_to_nft(value: Immediate) -> JsonNftables:
+
+def imm_to_nft(value: Immediate) -> Any:
     if isinstance(value, range):
-        return {"range": [range.start, range.stop - 1]}
+        return {"range": [value.start, value.stop - 1]}
+
     elif isinstance(value, IPv4Network | IPv6Network):
         return {
             "prefix": {
@@ -57,13 +62,18 @@ def imm_to_nft(value: Immediate) -> JsonNftables:
                 "len": value.prefixlen,
             }
         }
+
     elif isinstance(value, set):
-        return {"set": [imm_to_nft(e) for e in value]}
+        return {"set": [expr_to_nft(e) for e in value]}
+
     return value
 
 
-# Expressions
-Expression = Ct | Fib | Immediate | Meta | Payload
+def expr_to_nft(value: Expression) -> Any:
+    if isinstance(value, get_args(Immediate)):
+        return imm_to_nft(value)  # type: ignore
+
+    return value.to_nft()  # type: ignore
 
 
 # Statements
@@ -98,8 +108,8 @@ class Match:
     def to_nft(self) -> JsonNftables:
         match = {
             "op": self.op,
-            "left": imm_to_nft(self.left),
-            "right": imm_to_nft(self.right),
+            "left": expr_to_nft(self.left),
+            "right": expr_to_nft(self.right),
         }
 
         return {"match": match}
@@ -115,7 +125,7 @@ class Verdict:
         return {self.verdict: self.target}
 
 
-Statement = Counter | Goto | Match | Verdict
+Statement = Counter | Goto | Jump | Match | Verdict
 
 
 # Ruleset
@@ -206,9 +216,7 @@ class Table:
     sets: list[Set] = field(default_factory=list)
 
     def to_nft(self) -> list[JsonNftables]:
-        commands = [
-            {"add": {"table": {"family": self.family, "name": self.name}}}
-        ]
+        commands = [{"add": {"table": {"family": self.family, "name": self.name}}}]
 
         for set in self.sets:
             commands.append(set.to_nft(self.family, self.name))