Mapping XML schema to Ladon types

class MessageAbstractType(LadonType):
    AP_Info: AP_InfoType
    MSSP_Info: MSSP_InfoType
    MajorVersion = {
        'type': int,
        'nullable': False}
    MinorVersion = {
        'type': int,
        'nullable': False}

class AP_InfoType(LadonType):
    AP_ID = {
        'type': unicode, #xs:anyURI
        'nullable': False}
    AP_TransID = {
        'type': unicode, #xs:NCName
        'nullable': False}
    AP_PWD = {
        'type': unicode, #xs:string
        'nullable': False}
    Instant = {
        'type': unicode, #xs:dateTime TODO should we take it as a string?
        'nullable': False}
    AP_URL = {
        'type': unicode, #xs:anyURI
        'nullable': True}

class MSSP_InfoType(LadonType):
    MSSP_ID: MeshMemberType
    Instant = {
        'type': unicode, #xs:dateTime TODO
        'nullable': True}


class MeshMemberType(LadonType):
    DNSName = {
        'type': unicode,
        'nullable': True} #TODO minOccurs="0", is it the same?
    IPAddress = {
        'type': unicode,
        'nullable': True} #TODO
    URI = {
        'type': unicode,
        'nullable': True} #TODO
    IdentifierString = {
        'type': unicode,
        'nullable': True} #TODO