diff --git a/src/main/scala/ch/usi/si/msde/edsl/lecture10/GenerativeFluentAssertionsDSL.scala b/src/main/scala/ch/usi/si/msde/edsl/lecture10/GenerativeFluentAssertionsDSL.scala
index 2c252d3..165d4d9 100644
--- a/src/main/scala/ch/usi/si/msde/edsl/lecture10/GenerativeFluentAssertionsDSL.scala
+++ b/src/main/scala/ch/usi/si/msde/edsl/lecture10/GenerativeFluentAssertionsDSL.scala
@@ -72,7 +72,7 @@ object GenerativeFluentAssertionsDSL:
       // and the type of the property (actually... not exactly that. Why?)
       case '{
             (${ typeProvider }: HavePropertyTypeProvider[subjectType])
-              .applyDynamic($propertyNameExpr)($valueExpr: valueType)
+              .applyDynamic($propertyNameExpr)($valueExpr: valueType => Boolean)
               .$asInstanceOf$[AssertionProperty]
           } =>
         val subjectExpr = '{ $typeProvider.subject }
@@ -141,7 +141,7 @@ object GenerativeFluentAssertionsDSL:
   private def generateShouldHaveAssertion[T, R](
       subjectExpr: Expr[T],
       propertyNameExpr: Expr[String],
-      propertyValueExpr: Expr[R]
+      propertyValueExpr: Expr[R => Boolean]
   )(using Type[T], Type[R])(using Quotes): Expr[Unit] =
     import quotes.reflect.*
 
@@ -174,12 +174,11 @@ object GenerativeFluentAssertionsDSL:
        */
       val assertion = '{
         val subject = $subjectExpr
-        val expectedValue = $propertyValueExpr
-        lazy val result = ${ Select(('subject).asTerm, candidateMethod).asExpr }
+        val tester = $propertyValueExpr
+        lazy val value = ${ Select(('subject).asTerm, candidateMethod).asExprOf[R] }
         assert(
-          result == expectedValue,
-          s"${subject} did not have ${$propertyNameExpr} equal" +
-            s" to ${expectedValue}, but it was equal to ${result}"
+          tester.apply(value),
+          s"assertion failed for ${subject}.${$propertyNameExpr}"
         )
       }
       report.info(assertion.show, subjectExpr.asTerm.pos)
diff --git a/src/main/scala/ch/usi/si/msde/edsl/lecture10/Main.scala b/src/main/scala/ch/usi/si/msde/edsl/lecture10/Main.scala
index d429dac..a926744 100644
--- a/src/main/scala/ch/usi/si/msde/edsl/lecture10/Main.scala
+++ b/src/main/scala/ch/usi/si/msde/edsl/lecture10/Main.scala
@@ -40,7 +40,7 @@ case class Box(label: String, weight: Mass, price: Money)
     // assert(List(1,2,3).nonEmpty)
     List(1, 2, 3) should be.nonEmpty
 
-    (person should have) age ((x: Int) => x == 10)
+    person should have age satisfying >= 10
 
     // New syntax for `be` with type provider
     // either adult is a method with a dummy Unit parameter