Possible error in MessageMedia.Messages.Models.Message

[jason-russell]

I think there's an error in the (C#) model for Message
According to the documentation:

Specifying a source number type is only valid when the source_number parameter is specified and is optional

However in the model, this is a non-nullable property:

/// <summary>
/// Type of source address specified
/// </summary>
[JsonProperty("source_number_type", NullValueHandling = NullValueHandling.Ignore)]
[JsonConverter(typeof(StringEnumConverter))]
public NumberType SourceNumberType { get; set; }

I think this needs to be nullable

public NumberType? SourceNumberType { get; set; }  

When I try to submit a message where this is non-nullable, the response fails with an internal error.