There is an inconsistency in the library for this field name. It is used in service bus Topic and Queue classes. In one, it uses max_size_in_mega_bytes, in the other it’s max_size_in_megabytes.

In addition to the inconsistency, there is a bug in the convert_topic_to_xml function:

    if topic.max_size_in_mega_bytes is not None:
        topic_body += ''.join(['<MaxSizeInMegabytes>', str(topic.max_size_in_megabytes), '</MaxSizeInMegabytes>'])

I propose we use max_size_in_megabytes everywhere for the field name. The HowTo guides for Topic and Queue are both showing code examples that use max_size_in_megabytes (so one of the guides is currently wrong).