hide object property from dir() function?

[jerryji]

Hi,

Sorry for this newbie question, I was puzzled why the existing
property of an object is not shown in the dir() function output.

"v" is an lxml Element object variable --

In [44]: v
Out[44]: <Element 'documentProperties' at 0x8363cf8>

In [45]: dir(v)
Out[45]:
['__copy__',
 '__deepcopy__',
 '__reduce__',
 'append',
 'clear',
 'find',
 'findall',
 'findtext',
 'get',
 'getchildren',
 'getiterator',
 'insert',
 'items',
 'keys',
 'makeelement',
 'remove',
 'set']

dir() output doesn't contain the ".tag", which does exist --

In [46]: v.tag
Out[46]: 'documentProperties'

what is the rule governing the display of a property from dir()?

Many thanks in advance!

Jerry