code: protected LightweightTypeReference getMapExpectation(LightweightTypeReference expectation) {
  		if (expectation != null && expectation.isResolved()) {
  			LightweightTypeReference result = expectation.getSuperType(Map.class);
  			if (result != null && result.getTypeArguments().size() == 2) {
  				return result;
  			}
  		}
  		return null;
  	}
docs: If the expected type is a subtype of {@link Map}, the resolved super type is returned.
  This allows to query for the type arguments that are available on the expectation.