     let constraint = NSLayoutConstraint(
         item: lhs.view!, attribute: lhs.attribute,
         relatedBy: relatedBy,
-        toItem: nil, attribute: .NotAnAttribute,
+        toItem: nil, attribute: .notAnAttribute,
         multiplier: 1.0, constant: constant)
     return constraint
 }


// MARK: - x <= y
public func <= (lhs: ConstraintTerm, rhs: ConstraintTerm) -> NSLayoutConstraint {
    return createLayoutConstraint(lhs, relatedBy: .LessThanOrEqual, rhs: rhs)
}

// MARK: - x <= c
public func <= (lhs: ConstraintTerm, rhs: CGFloat) -> NSLayoutConstraint {
    return createLayoutConstraint(lhs, relatedBy: .LessThanOrEqual, rhs: rhs)
}

public func <= (lhs: ConstraintTerm, rhs: Int) -> NSLayoutConstraint {


// MARK: - x >= y
public func >= (lhs: ConstraintTerm, rhs: ConstraintTerm) -> NSLayoutConstraint {
    return createLayoutConstraint(lhs: lhs, relatedBy: .greaterThanOrEqual, rhs: rhs)
}

// MARK: - x >= c
public func >= (lhs: ConstraintTerm, rhs: CGFloat) -> NSLayoutConstraint {
    return createLayoutConstraint(lhs: lhs, relatedBy: .greaterThanOrEqual, rhs: rhs)
}

public func >= (lhs: ConstraintTerm, rhs: Int) -> NSLayoutConstraint {
