         self.constant = other
         return constrainTo(ConstraintItem(view: nil, attributes: ConstraintAttributes.None), relation: relation)
     }
+    private func constrainTo(other: Double, relation: ConstraintRelation) -> Constraint {
+        self.constant = other
+        return constrainTo(ConstraintItem(view: nil, attributes: ConstraintAttributes.None), relation: relation)
+    }
     private func constrainTo(other: CGSize, relation: ConstraintRelation) -> Constraint {
         self.constant = other
         return constrainTo(ConstraintItem(view: nil, attributes: ConstraintAttributes.None), relation: relation)

        self.priority = priority
        return self
    }
    public func priorityRequired() -> Constraint {
        return priority(1000.0)
    }
    public func priorityHigh() -> Constraint {
        return priority(750.0)
    }
    public func priorityLow() -> Constraint {
        return priority(250.0)
    }
    
    // MARK: offset

        self.offset = amount
        return self
    }
    public func offset(amount: Double) -> Constraint {
        return self.offset(Float(amount))
    }
    public func offset(amount: CGFloat) -> Constraint {
        return self.offset(Float(amount))
    }
    public func offset(amount: Int) -> Constraint {
        return self.offset(Float(amount))
    }
    public func offset(amount: UInt) -> Constraint {
        return self.offset(Float(amount))
    }
    public func offset(amount: CGPoint) -> Constraint {
        self.offset = amount
