diff --git a/python/ommx/ommx/v1/__init__.py b/python/ommx/ommx/v1/__init__.py
index 20819eb2..d32c0894 100644
--- a/python/ommx/ommx/v1/__init__.py
+++ b/python/ommx/ommx/v1/__init__.py
@@ -994,8 +994,29 @@ def _as_pandas_entry(self) -> dict:
         } | {f"parameters.{key}": value for key, value in v.parameters.items()}
 
 
+class AsConstraint(ABC):
+    def __le__(self, other) -> Constraint:
+        return Constraint(
+            function=self - other, equality=Equality.EQUALITY_LESS_THAN_OR_EQUAL_TO_ZERO
+        )
+
+    def __ge__(self, other) -> Constraint:
+        return Constraint(
+            function=other - self, equality=Equality.EQUALITY_LESS_THAN_OR_EQUAL_TO_ZERO
+        )
+
+    def __req__(self, other) -> Constraint:
+        return self == other
+
+    def __rle__(self, other) -> Constraint:
+        return self.__ge__(other)
+
+    def __rge__(self, other) -> Constraint:
+        return self.__le__(other)
+
+
 @dataclass
-class Linear:
+class Linear(AsConstraint):
     """
     Modeler API for linear function
 
@@ -1232,28 +1253,9 @@ def __eq__(self, other) -> Constraint:  # type: ignore[reportIncompatibleMethodO
             function=self - other, equality=Equality.EQUALITY_EQUAL_TO_ZERO
         )
 
-    def __le__(self, other) -> Constraint:
-        return Constraint(
-            function=self - other, equality=Equality.EQUALITY_LESS_THAN_OR_EQUAL_TO_ZERO
-        )
-
-    def __ge__(self, other) -> Constraint:
-        return Constraint(
-            function=other - self, equality=Equality.EQUALITY_LESS_THAN_OR_EQUAL_TO_ZERO
-        )
-
-    def __req__(self, other) -> Constraint:
-        return self == other
-
-    def __rle__(self, other) -> Constraint:
-        return self.__ge__(other)
-
-    def __rge__(self, other) -> Constraint:
-        return self.__le__(other)
-
 
 @dataclass
-class Quadratic:
+class Quadratic(AsConstraint):
     raw: _Quadratic
 
     def __init__(
@@ -1448,7 +1450,7 @@ def __neg__(self) -> Linear:
 
 
 @dataclass
-class Polynomial:
+class Polynomial(AsConstraint):
     raw: _Polynomial
 
     def __init__(self, *, terms: dict[Iterable[int], float | int] = {}):
@@ -1633,7 +1635,14 @@ def __neg__(self) -> Linear:
 
 
 def as_function(
-    f: int | float | DecisionVariable | Linear | Quadratic | Polynomial | _Function,
+    f: int
+    | float
+    | DecisionVariable
+    | Linear
+    | Quadratic
+    | Polynomial
+    | _Function
+    | Function,
 ) -> _Function:
     if isinstance(f, (int, float)):
         return _Function(constant=f)
@@ -1647,12 +1656,14 @@ def as_function(
         return _Function(polynomial=f.raw)
     elif isinstance(f, _Function):
         return f
+    elif isinstance(f, Function):
+        return f.raw
     else:
         raise ValueError(f"Unknown function type: {type(f)}")
 
 
 @dataclass
-class Function:
+class Function(AsConstraint):
     raw: _Function
 
     def __init__(
@@ -1888,7 +1899,13 @@ class Constraint:
     def __init__(
         self,
         *,
-        function: int | float | DecisionVariable | Linear | Quadratic | Polynomial,
+        function: int
+        | float
+        | DecisionVariable
+        | Linear
+        | Quadratic
+        | Polynomial
+        | Function,
         equality: Equality.ValueType,
         id: Optional[int] = None,
         name: Optional[str] = None,