1. override
Constraint equals(EquationMember value)

Creates a Constraint by using this member as the left hand side expression and the argument as the right hand side Expression of a Constraint with a Relation.equalTo relationship between the two.

For example: topEdgeOfBoxA + cm(10.0) == topEdgeOfBoxB woud read, "the entities A and B have a padding on top of 10."

Source 

@override
Constraint equals(EquationMember value) {
  return _createConstraint(value, Relation.equalTo);
}