Mapping attribute in DynamoDBDocument that can be of type S or N does not work

[maxvandewiel]

I am unable to to Map a attribute in de DB Document that depending on the record/document in the DB is of type N, S OR M?
Using Item gives me a empty result however the attribute in de document in the DB contains items.

i.e.
{
...
"data": {
"M": {
"value": {
"S": "Word"
}
}
}...
}

{
...
"data": {
"M": {
"value": {
"N": 244
}
}
}...
}