gen.py does not support properties that are List and have no Resources

[mparaz]

I can try fixing it, I just need some guidance.

For example:

    "AWS::LakeFormation::DataLakeSettings.Admins": {
      "Type": "List",
      "Required": false,
      "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-lakeformation-datalakesettings-admins.html",
      "ItemType": "DataLakePrincipal",
      "UpdateType": "Mutable"
    }

    "AWS::LakeFormation::DataLakeSettings": {
      "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-lakeformation-datalakesettings.html",
      "Properties": {
        "Admins": {
          "Type": "Admins",
          "Required": false,
          "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-lakeformation-datalakesettings.html#cfn-lakeformation-datalakesettings-admins",
          "UpdateType": "Mutable"
        }
      }
    },

Has the output:

class Admins(AWSProperty):
    props = {
    }

class DataLakeSettings(AWSObject):
    resource_type = "AWS::LakeFormation::DataLakeSettings"

    props = {
        'Admins': (Admins, False),
    }

When I think it should be:

class DataLakeSettings(AWSObject):
    resource_type = "AWS::LakeFormation::DataLakeSettings"

    props = {
        'Admins': ([DataLakePrincipal], False),
    }