Moq: How to Setup ToDictionary

Question

I want to mock a Linq expression that returns a Dictionary<string, string>

Dictionary<string, string> properties = new Dictionary<string, string>()
{
    { "Service", "serviceTest" }
}

equipment.SetProperties(dmsElement.Properties.ToDictionary(x => x.Definition.Name, x => x.Value));

Here is the unit test

fakeEquipment.Setup(e => e.Properties.ToDictionary(It.IsAny<Func<IDmsElementProperty, string>>(), It.IsAny<Func<IDmsElementProperty, string>>())).Returns(properties);

I am getting the following error:

System.NotSupportedException: 'Unsupported expression: ... => ....ToDictionary<IDmsElementProperty, string, string>(It.IsAny<Func<IDmsElementProperty, string>>(), It.IsAny<Func<IDmsElementProperty, string>>())

How can I setup the ToDictionary method to retrieve the expected values?